Forest Farming

Each riparian agroforestry practice has a different role within the context of a working riparian buffer. Buffers are typically broken out into different “zones” in which different practices are applicable in order to sufficiently protect water quality and create high quality habitat. The widths of the different zones, as well as the types of management applied in them, are determined by multiple factors, including regulations, budget, site conditions, water feature type and size, and landowner objectives.

• Zone 1 (Inner Zone) – The innermost zone of a buffer, sometimes called the “core zone”, is where the greatest water quality and habitat benefits are generated. This zone should be left relatively unmanaged as natural forest, ideally with abundant native species growing densely. While intensive management and harvesting practices should be avoided in this area, it can still be designed to provide opportunities for wild foraging and low impact forms of forest farming (e.g., berry picking, tree syrups, log-grown mushrooms). The width of this zone is typically 25-50′ depending on the type and size of water feature being buffered.
• Zone 2 (Middle Zone) – The area immediately adjacent to the inner zone also provides important riparian protection benefits, and should be managed to maintain a mostly closed forest canopy of native trees. However, this zone is suitable for more intensive forest farming practices (e.g., woods cultivated systems). Silvopasture may also be practiced in this area, if compatible with a closed tree canopy (e.g. flash grazing, living shelters). The width of this zone is typically between 25′-100′, depending on the size of the inner zone, water feature type and size, and landowner objectives.
• Zone 3 (Outer Zone) – The outer most zone is the most flexible to practices that require reduced tree cover like alley cropping and more intensively managed silvopasture systems. The presence of trees and/or shrubs in this zone provides additional benefits to riparian habitat, but it is less critical to maintain a closed forest canopy at this distance from a water feature. The width of the outer zone will vary based on landowner objectives, size of the other two zones, and recommended buffer size for the site. For example, the WA Department of Ecology recommends a 215′ total buffer width between all zones, although this is not always feasible.

The topography of a site is described by its slope, aspect, and elevation.  These factors can have significant influence on what kind of vegetation grows naturally in that area, as well as what could be cultivated. 

Elevation is not likely to vary enough within a given site to have significant impacts on what can be grown there but knowing the elevation range of your site is important.  Higher elevations are more likely to experience freezing conditions during the winter months and will have a slightly shorter growing season, which may not be suitable for some crops.  Small changes in elevation within a site can also impact site conditions.  For instance, low areas where cool air collects and cannot easily escape create frost pockets.  These areas experience freezing conditions earlier in the fall and later in the spring, which can damage new growth on plants.  Identifying frost pockets during planning and designing them with frost-hardy species can help avoid damage or mortality.  Similarly, upslope areas and ridgetops are generally subject to greater wind pressure, which can damage trees and reduce air and soil moisture.

Slope measures the steepness, or gradient, of a given site and is often expressed as a percentage (e.g. 20% slope) or a degree (e.g. 10° slope).  Many riparian buffers will include sloped areas like streambanks.  The intensity of slope will affect how water drains, organic matter accumulates, and the level of difficulty involved in maintaining a forest farming system.  Gentle to moderate slopes of 5-15% are generally ideal for forest farming because they allow for adequate drainage and organic matter accumulation, while remaining easily workable.  Steeper slopes may be viable but are more difficult to maintain.  Flat slopes (less than 5%) are also suitable for forest farming but are more likely to have poor drainage.  These sites should be monitored during the winter months to determine if there is a risk of ponding or overly saturated soils that could would affect crop selection.  See the Soils section for more information on how soil drainage can impact crop selection.

Aspect describes the cardinal direction that a slope faces.  North and east facing slopes will experience less intense sun exposure and usually have greater moisture availability.  These sites are better for crops that have higher moisture demands or are sensitive to heat. South and west facing slopes are exposed to direct mid-day and afternoon sun and face greater heat stress and soil evapotranspiration.  For sites like this, crops that are more tolerant of dry conditions and heat may be more suitable, such as Oregon grape.  West-facing slopes are also likely to experience greater wind pressure, especially closer to the coast.  Extreme wind events may damage understory crops and overstory trees.  Dry winds can have a desiccating effect that can reduce relative humidity and moisture availability. The aspect that is best for your forest farming system will be highly dependent on the crops you select and their site needs. In the northeastern United States, ginseng is commonly grown on north and east facing slopes to take advantage of the greater moisture (Burkhart, 2024).  It can still be grown on other aspects but may require special care.  It should also be noted that greater soil moisture and relative humidity because of aspect or other site conditions can increase the risk of disease in some crops. 

Soil characteristics, including texture, acidity, drainage, and organic matter levels, will have significant influence on a forest farming system.  Soil traits can vary significantly even in small areas.  Over time, land managers come to know variations in their soils well, especially in terms of hydrology.  Riparian buffers are likely to have more consistent soil characteristics because of their proximity to water features but prospective forest farmers should keep this potential variation in mind when planning and designing a buffer. 

Soil texture refers to the relative amount of sand, silt, and clay in a soil.  The texture effects how water moves through the soil (i.e. drainage). By nature, riparian soils will have greater moisture content compared to upland habitats but can still include a range in textures, from well drained, sandy soils to hydric, clay soils.  This is especially true along the gradient of a slope.  Upper slopes will be better drained than toe slopes or flat areas adjacent to a waterway.  Many tree species have high moisture needs but don’t do well in standing water and instead prefer sites where water is available as it drains through the soil, such as bigleaf maple (Acer macrophyllum) or western redcedar (Thuja plicata).  Understory crops can be equally affected by drainage. For instance, ramps (Allium tricoccum) can grow well in moist soils on toe slopes next to streams or adjacent to wetlands where the soils are slightly better drained.  Others, like wasabi (Eutrema japonicum) or Devil’s Club (Oplopanax horridus), require saturated soils year-round.  It’s also important to consider seasonal changes in water levels throughout the year and how that could impact a potential crop.  Plants growing in overly wet conditions that are not adapted to it may struggle to establish, grow poorly, or be subject to disease. 

You can determine the texture and drainage of soils on your property using the Natural Resource Conservation Service’s Web Soil Survey.  See the tools section at the end of this chapter for guidance on how to use this webtool for your property.  The Web Soil Survey can project a map of the soils on your property based on your region, elevation, slope, and other site factors.  It is often quite accurate, but it is still valuable to ground truth it by monitoring the hydrology of the area throughout the year and digging up soil samples to examine the texture. Use this NRCS guide (PDF) to learn more about testing soil texture by hand.

Acidity, nutrient levels, and organic matter content will also impact how different species are able to establish and grow.  These can only be determined through soil tests which requires taking samples and submitting them to a soils laboratory.  Testing may or may not be necessary for forest farming and will depend on whether the crops you’re interested in growing have specific nutrient demands.  Soil characteristics can vary widely throughout a forested area, which makes accurate testing in this context difficult.  So, for forest farming applications, it’s better to do multiple tests in a smaller area than doing a few samples across a broad area.  You may also be able to use existing vegetation as an indicator of soil conditions (see the Indicator Species section).  Ideal soil characteristics will vary depending on the species you intend to grow, and some species are more sensitive than others to being grown outside those conditions.  Soil amendments can be used to improve nutrients, increase organic matter, and manipulate acidity but should applied carefully and minimized in riparian buffers. Visit this WSU Extension webpage for more resources on soil testing. 

Channel migration zones (CMZ) are areas where a stream or river channel has the potential to move over time. These occur in floodplains and are the result of gravity, topography, and periods of heavy rainfall. Although they can cause problems for land managers and pose safety threats to communities located near rivers, they are ecologically valuable due to a high diversity of aquatic habitats.

Planning a working riparian buffer in a CMZ poses obvious challenges and risks, and increased heavy rainfall events as a result of climate change is increasing the risk in these spaces. Migrating channels along large waterways have the power to topple mature trees and severely alter forests. Smaller streams and waterways can also experience channel migration, but damage is typically less significant. Although there are methods available for mitigating the impacts of channel migration, these typically require modification of the stream bank and significant investment, making them unfeasible for most producers and subject to regulatory barriers.

However, if your property is in a CMZ it doesn’t mean you should avoid investing in riparian agroforestry or restoration. Like wildfire or other natural disasters, these are long-term risks, and areas may go decades without any or minimal issues. Furthermore, damage from channel migration can range significantly and won’t necessarily devastate a riparian agroforestry system, especially along smaller streams. The best strategy is to determine your level and scale of risk, if any, and adjust your management accordingly.

CMZ’s are most likely to occur in the inner and middle zones of a buffer, especially on smaller waterways, so forest farming systems in working buffers are subject to the most risk. However, CMZ’s can be large and, in some cases, encompass the entire area you have planned for a buffer. When present, understanding where the CMZ ends on your property will impact the width of your buffer and individual zones, as well as what practices you apply there.

Agroforestry systems are inherently long-term systems and long-term investments, but some forest farming crops are better suited to areas at high risk to disturbances like CMZs. For instance, forest cultivated shiitake systems can be moved if necessary. Tree syrup operations can also function in a CMZ, although sap collection systems and crop trees may be damaged by flooding. Ground crops face the greatest impacts from channel migration. In this case, short-term crops are better suited to high risk areas compared to crops that require significant time to mature, such as ginseng or fruit-producing shrubs. Channel migration can also severely effect trees and tree crops. Powerful surges in large waterways can topple trees and long-term changes in hydrology will affect what can survive there. This doesn’t mean you shouldn’t plant trees in CMZs, in fact deep rooted trees can help mitigate erosion damage during channel migration, but selecting tree and crop species with long-term risk in mind is important during the design process.

Many landowners are not effected by channel migration. Identifying a CMZ and determining if a property is at risk requires a thorough study and is a task for an experienced professional. The Washington Department of Ecology has compiled a catalogue of planned and completed publicly available CMZ studies into the Channel Migration Zone Spatial Data Catalogue. Most counties also provide resources and CMZ studies on their websites. However, many streams and rivers remain unstudied. Technical assistance providers, such as conservation districts or NRCS agents, can provide some assistance in identifying basic risk of channel migration, but may not always be equipped to provide detailed assessments.

Read more:

• Stream Channel Migration Zones – Washington Department of Ecology
• CMZ Story Map – Oregon Department of Geology and Mineral Industries

The composition and structure of existing vegetation can provide valuable information about the site.  A plant that requires specific site conditions to grow can be considered an indicator species.  The presence of these species indicates those conditions are present at a given site, such as soil drainage, acidity, nutrient concentrations, or organic matter levels.  The presence or absence of some species, specifically mosses and lichen, can even help determine the air quality of an area.  Devil’s club is a good example of an indicator species because it typically grows in wetlands sites with poor drainage where soils are saturated for much of the year.  It grows near skunk cabbage (Lysichiton americanus), western redcedar, and lady fern (Athyrium filix-femina), creating a wetland plant community.  Similarly, wild lily of the valley (Maianthemum dilatatum) requires moist, well-drained loamy soils high in organic matter and is often found growing alongside sword fern (Polystichum munitum), red elderberry (Sambucus racemosa), and red huckleberry (Vaccinium parvifolium) in the understory and an overstory with a significant hardwood component, such as bigleaf maple.  There is often overlap between plant communities and habitats, especially in transition areas, but identifying and inventorying the relative abundance of species growing and researching the growing conditions they prefer will help you determine the characteristics of your site.  Keep in mind that noxious weeds like Himalayan blackberry, Scotch broom, or English ivy are typically competitive across a wide range of sites and do not reliably indicate site conditions. 

For individuals establishing a new buffer where few native indicator species are available (e.g. pasture or noxious weeds), relying on topography and soils information will help determine what plant community may have existed on that site previously.  When planning for non-native species the goal is to find sites and conditions that are analogous to their native habitat.  For instance, in the eastern U.S. ginseng grows in calcium-rich soils with high organic matter content on northeast slopes, often beneath sugar maple (Acer saccharum) (Burkhart, 2024).  In Washington, sites dominated by bigleaf maple, whose leaf litter increases calcium and other macronutrients in the soil (Turk et al., 2008), produce similar conditions and may facilitate ginseng forest farming.  WSU Extension is currently exploring this with field trials and the findings will be shared in this Toolkit when they are available. For more information on systematically recording indicator species, see the Forest Inventory section.

Manipulating a forest overstory to achieve ideal light conditions in the understory is a key component of both establishing and maintaining a forest farm.  Shade levels are influenced by both the structure and composition of the overstory.  Dense forest canopies prevent light from reaching the forest floor while low-density forests will have greater light availability.  Conifers provide shade year-round while deciduous (i.e. hardwood) trees only provide shade from April to October.  The intensity, type, and timing of shade significantly influence what can be grown there.  For instance, spring ephemerals, such as ramps (Allium spp.) or nettle (Urtica spp.), grow best in deciduous forests because they complete most of their growth during early season while light availability is high before the trees leaf out.  Whether planting a new forest or modifying an existing one, understanding how shade impacts understory growth is critical.  

To determine the amount of light reaching the forest floor, foresters use a tool called a densiometer. This is a handheld device with a concave or convex mirror with a grid engraved on it, which allows you to measure the amount of light reflected at a given point in the understory.  A densiometer is relatively inexpensive and can be a worthwhile investment for anyone managing long-term forest farming systems, but a low budget workaround is also available using simple household materials (see below).

Paper Plate Method

 “Place 10 or more white paper plates at even distances on the ground at approximately noon on a sunny summer day. Count the number of plates that are at least half shaded. Next, divide the number of shaded plates by the total number of plates placed on the ground. Multiply this number by 100 [to determine shade percentage].” (Apsley & Carrol, 2013)

It can be helpful to take multiple measurements throughout the day to determine how shade changes over time.

Using a densiometer or the paper plate method will help you find an ideal site for your selected crop, or help you determine whether to manipulate the overstory to increase the amount of light available.  This can be done with thinning and/or pruning, which is described in the “Adapting a Forest for Forest Farming” section.  Optimum shade levels will vary by crop species and is typically described as percentage, although sometimes more general terms are used (e.g., dense shade, moderate shade, etc.).

For more information on how to systematically assess shade throughout a forest, see the Forest Inventory section.

Choosing a site that is accessible for you and your equipment is essential to establishing and maintaining a forest farm.  Ideal sites will be close to your residence and a limited distance from roads, pathways, or other access points. Although not always necessary, it can be beneficial to be within an operational distance of water and electricity.  This is especially true for forest cultivated mushroom systems (i.e. shiitake) or any crops requiring irrigation. 

• Select sites that are close to your residence to allow you to regularly check your plots and avert potential poachers
• Distribute smaller plots over a larger area rather than having one large plot
• Maintain or allow thick vegetation to grow along forest edges, roadways, etc. to reduce visibility
• Mark your boundaries with no trespassing signs
• Install wildlife cameras
• Utilize fencing and cameras if necessary

Not all of these will be appropriate or necessary for everyone, but when applied may reduce your risk of loss to theft. 

There are several tools available to landowners to conduct an “armchair assessment” of your property.  These provide helpful background information to compliment your observations on the ground.

• Google Earth
  • Google Earth is a free mapping program that utilizes satellite images to create maps.  It can be used in your web browser, or the “pro” version is available for free download to use on your desktop.  Using this program, you can create layers delineate roads, planting areas, and forest farming plots to plan and track your operations.  You can also access historic aerial photos to determine past land use on your site.
• NRCS Web Soil Survey
  • The Web Soil Survey is a free online tool that generates a soil map which delineates and describes the different soils on your property.  The actual soil type boundaries can vary, so it is recommended to ground truth them to the best of your ability.  It also generates ratings for soil types against land use practices, such as susceptibility to compaction.  For more information on how to generate a Web Soil Survey report for your property, read the WSU Extension Manual EM064 “Forest Soil Data for Your Forest Stewardship Plan”.
• LandMapper
  • LandMapper is a powerful mapping tool created by EcoTrust and is specifically available to landowners in Oregon and Washington (as of 2024).  Using your address, this program auto-generates several maps, including hydrology, stream type, soil type, forest communities, tree diameter class, canopy cover, and forest density.  
• County-based parcel maps
  • Most counties offer an online GIS portal where you can gain access to information about your parcel, including aerial photos.  These portal maps often include layers with information related to local regulations, such as protected wetlands.  For information on your parcel, find your local county assessor’s office website. 

Keep Reading – Site Assessment

• Forest Farming Site Selection and Preparation Guidelines – Lincoln University of Missouri (PDF)
• How, When, and Why of Forest Farming:   – Cornell University
• Forest Farmer’s Handbook – Rural Action and United Plant Savers – Chapter 1: Site Assessment (PDF)

Tree arrangement is a key decision point for any planting project. There are several design approaches available for afforestation projects, each with their own benefits, drawbacks, and ideal applications.  The sections below describe multiple different approaches to planting design and how forest farming can be integrated into them.

Traditional

A traditional afforestation approach utilizes a similar approach to what would occur in a reforestation scenario after a large-scale disturbance like a timber harvest or wildfire.  Trees are planted on a grid which results in equidistant spacing.  A traditional spacing and density in the Pacific Northwest is usually between 10’ x 10’ (436 trees per acre) and 12’ x 12’ (303 trees per acre).  Mortality is common in afforestation scenarios, so planting at a higher density can compensate for anticipated mortality as result of difficult site conditions.  The greater competition between trees in high density plantings also encourages prioritization of height growth in trees and will lead to faster canopy closure, which can facilitate forest farming sooner.  Higher density plantings usually require thinning after canopy closure to mitigate long-term competition and associated forest health issues, as well as to maintain ideal light conditions for forest farming.

Traditional timber plantations typically consist of one species.  Planting a mix of species, including both deciduous and coniferous trees, is recommended in a riparian buffer to maximize diversity and habitat benefits.  This also presents an opportunity to plant “crop” trees that yield non-timber products, such as western redcedar for boughs, red alder for shiitake logs, or bigleaf maple for maple syrup.  You could elect to clump different species together (to create a maple “sugarbush”, for instance) or scatter them throughout a buffer.

Variable Planting

Variable planting is a modified approach to traditional planting where a mix of planting densities and species compositions are used to create structural and species heterogeneity during stand establishment.  This approach can enhance the wildlife habitat benefits of a future forest, but also provides opportunity to “mix up” your approach and design a buffer to create conditions for multiple forest farming practices.  This is a great approach for a hobbyist forest farmer that wants to make the most of a small buffer and grow multiple crops for personal use.  At larger scales, this can help diversify income from a commercial forest farming operation.  Here are some tips and ideas for designing a buffer with a variable planting approach:

• Change up the density – Consider changing up your planting density throughout a buffer. Planting at higher densities immediately adjacent to waterways will provide greater water quality benefits over time, especially when adjacent to farmlands.  Lower densities may be ideal in areas where you are confident in seedling survival, may have limited access to be able to thin, or in areas you want greater light availability in the understory.  Keep in mind that different species will have different recommended spacings.
• Vertical diversity – Consider diversifying the vertical structure of your forested buffer by interplanting shrubs and small trees between your canopy trees or designing small canopy gaps (<0.25 acres) designated just for shrubs.  These can be good areas to create native “food forests” that can provide edible crops for personal use or commercial sale, but also provide significant wildlife habitat.  Many species can grow in shade but require greater light availability to produce viable yields, such as huckleberry, elderberry, osoberry, and hazelnut, and cultivating them in canopy gaps can facilitate better production.
• Consider a guild approach – A “guild” approach will help you design a buffer planting with a variety of species compositions.  Guilds are groups of species that tend to be found growing together in natural conditions and/or are well known to complement each other.  Guilds often include species that grow in the overstory, midstory, and understory, and are sometimes referred to as a “complex”.  For instance, salmonberry is often found growing abundantly in the midstory below a red alder dominant stand because it provides light shade and both flourish in riparian soils.  These could be paired together in a guild planting.  Understory forbs and potential crops are often introduced later after canopy closure or, alternatively, crops with higher light demands can be cultivated between newly planted trees and shrubs until canopy closure.

• Work around your site – When designing a planting of a diverse set of species, it’s important to be aware of the site conditions, including microsites.  Microsites are small areas where the conditions slightly differ from the surrounding area, such as small depression where water might collect or frost pockets.  Some species are better at tolerating these conditions than others, and this can be an opportunity to design your diversified planting around existing conditions.  For instance, Wet Feet Farming is an agroforestry approach designed specifically to tackle seasonally saturated areas of agricultural fields.  Similarly, there may be areas with degraded or excessively dry soils, frost pockets, or sensitive areas that require unique design.

The beauty of a variable planting approach is there are very few wrong ways to do it, but it does also require more thought and intention compared to a traditional tree planting.  Expect to go through several iterations of your planting design until you feel you’re adequately meeting your objectives.

Miyawaki Planting Method

The Miyawaki Planting Method is an afforestation approach developed by Japanese botanist and professor, Akira Miyawaki, to restore native forests on sites facing degraded conditions (Poddar, 2021).  It has primarily been studied in arid and tropical environments but may have potential for restoration efforts in the Pacific Northwest, particularly in challenging areas where previous afforestation efforts have failed.  The method relies on the idea of restoring a sites “potential natural vegetation” (PNV).  In practice, this means high density plantings of a wide variety of native trees and shrubs that eventually comprise the full vertical strata of a forest (overstory, midstory, and understory).  In doing so, the Miyawaki Method mimics natural revegetation of sites. A regional example of this would be to plant Oregon grape, osoberry, cascara, red alder, and western redcedar together because they will occupy different vertical positions in a forest canopy.

Species selected for planting should be closely examined for suitability to the site. The Miyawaki Method takes a similar approach as the “guild” method mentioned in the previous section, where trees and shrubs are selected in groupings that are known to grow well together but could also be selected for crop production.  However, the key feature of the Miyawaki Method is the density of planting, which recommends at least three plants per square meter (or roughly one plant every 1-2 square feet) (Poddar, 2021).  This is much higher than traditional afforestation or reforestation plantings.  The high density stimulates rapid height growth in the plants and forces quick canopy closure.  It also suppresses other competing vegetation and reduces need for maintenance beyond the first few years. However, competition between planted species may increase and the higher density will also significantly increase the cost of the project due to the added plant material and labor.  It’s also important to consider that dense plantings are difficult to access and provide limited light to the understory for forest farming, so greater thinning efforts will be required.  Given the increased cost, this method is likely best suited for smaller projects and/or targeting areas with notably difficult site conditions. 

Keep Reading

• Miyawaki Technique of Afforestation by Sourik Poddar

• Mini Forest Revolution by Hannah Lewis
• Miyawaki Method – Western Washington University

Alley Cropping

Alley Cropping is an agroforestry practice where rows of trees or shrubs are planted at distance that allows the cultivation of row crops in the “alleys” created between them (USDA, 2025).  In agricultural settings, alley cropping systems utilize wide buffers of 30 feet or more to ensure long-term light availability for row crops as the trees grow.  In riparian buffers, it’s best to allocate long-term alley cropping systems like these to the outer zone because they will have reduced tree cover compared to a forest (see the Alley Cropping Page).  However, an alley cropping tree arrangement can still be applied to plantings in an inner buffer and has several benefits, particularly if the space is already being used for row crops.  In this scenario you would apply a tighter row spacing of 10-20 feet to ensure canopy closure.  In the early years after planting, the space between tree rows can continue to be utilized for growing row crops while light availability remains high.  For farmers that were row cropping these spaces prior to planting, this can provide a transition period between land uses and mitigate the financial losses associated with sacrificing production in this area while trees establish.  As the canopy closes over the rows, landowners can transition to shade tolerant specialty crops like forest medicinals or forest cultivated mushrooms. Fast growing tree species can be used to create ideal shade conditions quickly, such as red alder or black cottonwood, but should be balanced against other objectives like tree crops and habitat benefits.

If you wanted to extend alley cropping into the outer zone of a buffer and maintain it as a long-term system there, you would utilize a wider spacing (20-60’) and might include non-native crop producing trees (e.g. chestnut, apple, etc.) (University of Missouri, 2018).  Alternatively, alley cropping designs can provide temporary grazing opportunities between rows.  However, this will likely require fencing to protect trees from the animals.  Learn more about this by visiting the Silvopasture page.

Ultimately, the method of afforestation that is right for you will depend on a combination of your goals, resources, and site conditions.  A mixture of methods may be the best approach. 

Although planting a new forest can be challenging, it presents a great opportunity to design a forest specifically for forest farming.  By selecting native overstory and midstory species that fit your economic, personal use, or environmental objectives, you can maximize the benefits your future forest will provide. 

Selecting trees that will produce valuable crops will maximize the income or personal use opportunities from your forest.  Examples of this include bigleaf maple for syrup, western redcedar for boughs, willow (Salix spp.) for basketry, and red alder (and other hardwoods) to use as substrate for forest cultivated shiitake.  Choosing multiple species that produce crops will diversify your income and potentially allow you to spread production throughout the year. 

The species you select to comprise your overstory during forest establishment will have significant impacts on the density and timing of shade.  This will dictate what you’re able to grow in the understory after canopy closure.  Although thinning and pruning are powerful tools that allow you to manipulate shade density, some shade characteristics can only be achieved by the presence of certain species.  For instance, the timing of shade provided by deciduous trees facilitate the growth of spring ephemerals like ramps and stinging nettle, which do most of their growing before overstory trees leaf out in the spring.  Shade density can vary significantly between species too. For instance, western redcedar produces a much denser shade than Douglas fir or Ponderosa pine.  Among hardwoods, bigleaf maple produces a denser shade than red alder, Oregon oak (Quercus garryana), or Oregon ash (Fraxinus latifolia).  Having a sense of what crops you intend to farm in the understory will help you determine what species or combination of species in the overstory will provide the ideal shade conditions.

The growth rate and form of trees can also influence a forest farming operation. In most cases, fast-growing trees with spreading crowns are favored for buffer establishment over slower growing trees.  This reduces the need for maintenance of newly planted areas and achieves canopy closure quicker to allow for establishing understory farming systems.  However, this must be balanced against other objectives like growing favored crop trees, creating and maintaining ideal shade conditions, and providing long-term habitat benefits to riparian areas. 

Forest resilience is key to maintaining a viable forest farming operations and there are opportunities to enhance the long-term health of buffers during species selection.  This refers to the ability of a forest to recover from and adapt to challenges, including both biotic (e.g. root disease, bark beetles) and abiotic (e.g. drought, wildfire) factors.  Matching the right species to the site will go a long way to enhance forest resilience by providing those trees with the conditions for vigorous growth.  This requires an intimate knowledge of the site you’re planting as well as a familiarity with the silvicultural characteristics of the trees you are planting. 

Climate change is expected to have significant impacts in the Pacific Northwest, including changes in precipitation, increased temperatures, and increases in severe weather (Frankson et al., 2022). Increased summer heat and extended drought (particularly spring drought) has already been tied to the decline of some species in western Washington, including western redcedar and bigleaf maple (Andrus et al., 2024; Betzen et al., 2021). This increases the importance of matching species to site, and also stresses the need to consider drought tolerant species. This is especially true on south and west facing slopes, dry or shallow soils, or along forest edges, in fields, or other open areas where drought and heat are exacerbated. Other climate resilience strategies, such as assisted migration may be worth exploring. Assisted migration involves sourcing seed for native plants from places with hotter, drier conditions or migrating species out of their habitat to match expected future conditions (Handler et al., 2018). Examples of this would be sourcing bigleaf maple seedlings with genetics from northwest Oregon to plant further north in western Washington (i.e. seed zone migration) or planting Oregon white oak outside of its normal habitat because of its drought tolerance (i.e. range expansion). These are low-risk forms of assisted migration, while higher risk practices would include migrating species from far outside of their native habitat, including non-native species like incense cedar or coast redwood (i.e. species migration).

Understanding local and regional pest pressures may also influence your species selection.  For instance, emerald ash borer is present in the Pacific Northwest and causes significant mortality in ash trees (Fraxinus spp.) so it is best to avoid or minimize planting ash while EAB spreads.  If you have significant pressure from animals in your area (e.g. deer/elk, black bear), you may consider planting trees that are less palatable to them, especially if you do not have the resources to adequately protect them. Some native pests are experiencing population growth or spreading to new areas as a result of hotter drier summers making trees more susceptible.  For instance, fir engraver beetle (Scolytus ventralis) populations often spike after bad drought years and can increase damage on true firs like noble fir (Abies procera), grand fir (Abies grandis), and sometimes Douglas-fir.  California five-spined ips (Ips paraconfusus Lanier) are expanding their range to the Puget Sound region and prey on two-needle pine species (Pinus spp.).  Being aware of these trends in forest pests will help you determine the best species for your forested riparian buffer.  The Washington Department of Natural Resources conducts annual monitoring of forest health pests and releases their findings in a Forest Health Highlights Report to support decision making in land management.

The conditions that support forest farming and the conditions that support fish and wildlife habitat overlap greatly, making it possible to design buffers that emphasize crop production while providing significant habitat benefits.  Still there are some strategies to consider for maximizing habitat.  Native species should be prioritized wherever possible, especially within fifty feet of a stream or other riparian feature.  These species will be more likely to provide the necessary food and cover for native wildlife and are more likely to be a resource for pollinators.  Non-native trees may not provide adequate habitat but can still help with water quality enhancement, so they can add value in the outer zone of a riparian buffer.  Diverse forests provide better habitat compared to single-species plantations.  This will also enhance a forest’s resilience to stressors like pests and disease or climate change.  Long-lived conifers can be particularly beneficial to the inner and middle zone of riparian buffers to provide long-term shade and down woody debris, but deciduous trees like bigleaf maple and red alder also provide benefits to streams.  For example, leaf litter inputs from hardwoods support populations of aquatic macroinvertebrates, which serve as important food sources for fish (Piccolo & Wipfli, 2002).  Bigleaf maple is also an important food source for pollinators in the early spring (USDA, 2016).  If providing habitat is a primary objective, researching the species present in your area and their required habitat could help inform your species selection. 

For more information on species selection, including species tables, planting templates, and nurseries that provide plants, visit the Additional Resources Page. Technical assistance may also be available to you through state and local programs. 

Keep Reading:

• Assisted Migration – USDA Northern Climate Hub
• Climate Impacts in the Northwest – USDA Northwest Climate Hub
• Climate Resilience Guides For Small Forest Landowners (Western Washington/Eastern Washington) – USDA Northwest Climate Hub
• Forest Health Highlights – Washington Department of Natural Resources
• Species and Habitats – Washington Department of Wildlife
• Trees of Washington – WSU Extension
• Washington Native Plant Society
• Woodland Fish and Wildlife

When ordering plants for your project, you may have the option to select from different stock types.  Stock type refers to how that plant was grown and maintained prior to planting.  Each stock type has advantages and disadvantages:

• Container plants are grown in containers with potting soil and can vary significantly in size.  Many niche plants, particularly shrubs and small trees, suitable for agroforestry are only available in containers from nurseries (e.g., chestnuts, tea plant).  Container plants are resistant to damage during transportation and typically have more established root systems, which increases survival. This makes them good for challenging sites. However, they are more expensive than other stock types.
• Bare root plants are grown in large quantities directly in the ground at large-scale nurseries for forestry and conservation plantings.  The plants are “lifted” in the winter while dormant and sold in bulk with their roots exposed.  In the period between lifting and planting, special care is required to ensure they remain dormant and roots don’t dry out.  Bare root plants have a lower survival rate than container plants, but they are also significantly cheaper. 
• Plugs are a type of container plant sold by forestry nurseries in bulk.  They are much smaller than typical container plants but are good for low-fertility sites and are less expensive. 
• Live stakes are segments cut from deciduous trees and shrubs that can be planted directly into the ground.  This is a form of asexual (vegetative) reproduction, which means the plant will be genetically identical to the plant it was harvested from.  Live stakes are very inexpensive and can be easily harvested from your own property, if available.  Willow and poplar (Populus spp.) are examples of species that can be easily propagated via cuttings. 

Many factors can influence the type of stock that is best for your project, but the primary influencers will be soil conditions and your budget.  Of course, the availability of seedlings in your preferred stock type can vary significantly from year to year and provider. 

Keep Reading:

• Plant the Right Tree Seedlings – WA DNR Webster Nursery

Site Preparation

Exactly as it sounds, the site preparation stage is intended to ready an area for tree planting and can include several practices necessary to improve conditions for the species you intend to plant, like soil amendments, vegetation management, and scarification.  However, in most cases, the primary goal of site preparation will be to eliminate any existing vegetation that will compete with the species you are planting while they’re getting established, which is what this section will focus on.  It’s common to see failed plantings where competing vegetation was not managed.  The presence of other vegetation, especially grass or noxious weeds, will reduce the water and nutrients available to your seedlings.  Some weeds, such as blackberry or Scotch broom, can easily grow over top of your seedlings and shade them out as well.  The effort required to prepare a site for planting a site will vary significantly based on the type and density of vegetation growing there.  At minimum, it is recommended to eliminate competing vegetation in a circle within 1-2 feet of the seedling. ‘Exactly as it sounds, the site preparation stage is intended to ready an area for tree planting and can include several practices necessary to improve conditions for the species you intend to plant, like soil amendments, vegetation management, and scarification.  However, in most cases, the primary goal of site preparation will be to eliminate any existing vegetation that will compete with the species you are planting while they’re getting established, which is what this section will focus on.  It’s common to see failed plantings where competing vegetation was not managed.  The presence of other vegetation, especially grass or noxious weeds, will reduce the water and nutrients available to your seedlings.  Some weeds, such as blackberry or Scotch broom, can easily grow over top of your seedlings and shade them out as well.  The effort required to prepare a site for planting a site will vary significantly based on the type and density of vegetation growing there.  At minimum, it is recommended to eliminate competing vegetation in a circle within 1-2 feet of the seedling. 

Site preparation typically occurs in the growing season ahead of when you intend to plant.  For instance, if you intend to plant in November, you might conduct your site preparation of the area sometime between May and September.  Generally, it is best to avoid too large of a gap between when you prepare a site and plant so there is limited time for vegetation to grow back. So, it can be advisable to wait until later in the growing season.  That said, the best timing for your site prep could vary significantly based on the type of vegetation there and method you choose.  For instance, an excellent method for removing invasive blackberry (e.g., Himalayan blackberry) is to cut it back to the ground in the early summer using hand tools or a brush hog, then allowing it to grow back over the remainder of the growing season.  Then, in the early fall, use a recommended herbicide to kill the new vegetation.  This late season herbicide application ensures the chemical is taken into the roots as the plants go into dormancy, and having mulched the bulk of the vegetation in the early summer ensures the area is accessible and easy to work in. 

For more recommendations on how to deal with specific weed species, visit the PNW Weed Management Handbook.  In some cases, site preparation may take more than one growing season to adequately remove existing vegetation.  In other cases, it may be as simple as removing grass and sod by hand immediately before planting. 

There are several methods of vegetation control available, many of which are described below.  Again, the most appropriate method will depend on the type and density of vegetation, other site conditions, and your available resources.  Integrated pest management (IPM) is strongly recommended, which is a strategy that utilizes multiple approaches to managing pests, including unwanted vegetation, efficiently and with limited ecological impacts. 

Chemical applications can be used to eliminate competing vegetation efficiently and effectively.  Most herbicides are used to kill existing vegetation, but pre-emergent herbicides are also available, which prevent seeds in the soil from sprouting. The use of herbicides in or near riparian areas should be limited whenever possible but may be the best or only viable option, especially for large scale projects where other methods would be too labor intensive or not financially feasible.  When using herbicides, always read the label and be aware that some have limited legal applications within certain distance of water and/or require special licensing.  For recommendations on chemical applications for specific weed species, refer to the PNW Weed Management Handbook.

Hand-weeding using basic tools can often be the most cost-efficient way to prepare a site for planting.  It’s effective for small-scale projects or bigger projects where minimal site preparation is necessary.  For instance, when planting in grassy areas, an effective strategy is to simply remove the sod layer within 1-2’ of the planting spot and set it aside immediately before planting. 

Sheet mulching, also referred to as “lasagna composting”, involves layering organic materials (typically 3-6” thick) over a project area.  This eliminates existing vegetation prior to planting and will continue suppress vegetation while trees are getting established.  Mulching is effective and utilizes materials like cardboard and woodchips, which can often be sourced for free or with limited cost.  It also adds organic matter to the soil over time.  However, it may add labor to the planting process, especially if you must cut through layers of carboard to get to the soil. Because of the materials required, it is generally more suitable for small to medium sized projects.  While mulch can effectively mitigate soil moisture loss through evaporation, it can also reduce soil recharge from rainwater, and may need to be paired with irrigation depending on the materials used.  Sheet mulch is also susceptible to being washed away in areas that flood, so it’s important that you know where flooding may occur on your site to determine where other strategies are more appropriate.

Keep Reading: 

• Sheet Mulching:  A Quick Guide to Getting Started – Pierce County Conservation District (PDF)

Solarization is the process of laying clear plastic over a project site to destroy existing vegetation.  The plastic covering creates a greenhouse effect, trapping heat and moisture, that kills the plants underneath.   This is best done during the growing season to take advantage of warm, sunny days.  Depending on the weather, solarization may take 2-3 weeks to effectively kill the vegetation beneath.  Occultation is a similar practice, but instead uses opaque materials (e.g. black plastic tarp).  Because the material is opaque the greenhouse effect is limited, and the process takes longer (often 3-6 weeks) but landowners are more likely to have these materials already so it can be the more cost-effective option.  Solarization and occultation will control vegetation prior to planting but are not recommended for controlling vegetation around planted trees because their heating effect on the soil may damage roots. Although research is limited on this practice, it may have the benefit of killing harmful organisms in the soil, but it will also destroy beneficial organisms.  Using an arbuscular mycorrhizal inoculant on the roots of plants during planting may help offset any negative effects solarization or occupation has had on beneficial soil biota. 

Keep Reading:

• Using the Sun to Kill Weeds – University of Minnesota Extension

• Soil Solarization: An alternative to soil fumigants – Colorado State University Extension

Tilling is a mechanical site preparation strategy that involves ripping or turning over soil in the areas you intend to plant.  This kills or sets back existing vegetation and makes soil more workable for planting.  This can be particularly helpful in areas with compacted soil and/or heavy clay components.  However, because tilling exposes soil it can create conditions for new weeds to flourish. “Strip tilling” in narrow rows just wide enough to plant in, rather than tilling the entire project area, is recommended.  This will limit the weed response and reduce potential for soil erosion. Tilling is sometimes followed with solarization, occultation, or chemical applications to kill the weeds that get established after tilling, thereby depleting the presence of weeds in the seed bed.  Tilling should be done carefully in riparian contexts and is not recommended on sensitive soils adjacent to riparian features or on slopes that would accelerate sedimentation into waterways

Mechanical means (i.e. machinery) may sometimes be necessary to efficiently remove existing vegetation.  This is especially true for larger projects and areas where there is significant woody vegetation or other difficult to remove species.  Tractors with mulcher attachments (i.e.) masticators and similar machines can make quick work of difficult vegetation and leave behind a thick layer of mulch.    However, large machinery should be avoided in sensitive riparian sites and wetland soils in winter or spring, or any time the ground is soft.  Smaller machines, such as brush hogs, may be necessary on sensitive sites and more effective for smaller projects and can often be rented from farm supply or hardware stores.

Planting

Whether you’re planting bare root, potted plants, or live stakes, timing is important.  In Western Washington, planting should occur after the soils have sufficiently recharged from the dry season and before plants come out of dormancy in the spring.  This is typically between November and April.  Planting in the fall can provide extra time for plants to establish roots ahead of their first growing season, which can improve drought tolerance and survival.  However, it can also expose plants to early frost damage and should be avoided for plants that are sensitive to frost (e.g. red alder) or in areas with significant frost pockets.

When planting bare root seedlings, be sure to ensure the roots stay moist and cool. Avoid planting on warm, sunny, or windy days. If the roots appear dry, it’s likely that many of the fine roots have already desiccated and are damaged, which makes survival unlikely. Waiting to pick up bare root seedings from the nursery until the day of or day before you intend to plant is recommended. Transport them in a cooler and keep out of the sun while you are working through the planting area. Bare root seedlings can be planted quickly using a dibble bar or planting shovel, which wedges in the ground to open a small gap allowing you to drop the seedling in. However, there are some easy mistakes to make, especially if moving quickly. See the figure to the right for some of the common pitfalls of planting bareroot seedlings and how to avoid them.

Keep Reading:

• Planting Forest Seedlings – Webster Nursery (PDF)
• Planting Trees and Shrubs in the Landscape – WSU Extension
• Selecting, Planting, and Caring for a New Tree – OSU Extension

Protection

In most cases, trees will require protection from animal damage.  Deer and elk are common in Washington and will browse the foliage and juvenile shoots of trees and shrubs.  This can set back their growth, cause poor form, or kill the tree entirely.  Small mammals, such as mice, voles, or rabbits, can also damage seedlings by girdling roots and stems.  The type and intensity of pest pressure will vary by site.  For instance, mice and vole damage can be particularly bad in overgrown pastures where they have significant cover from predators. 

There are two types of approaches to preventing animal damage to seedlings:  tree protection and cultural management.  There are several products and methods available for protecting individual or groups of trees.  Tree protectors (e.g. tree tubes) are the most commonly used method.  They can be used to protect the base and/or the leader of the trees while they establish.  However, they will add $1-2 in cost per tree and often require annual maintenance to move the tube up the tree 1-2 times a year as it grows to continue to protect the top of the tree from deer or elk browse.  Likewise, a t-post and fencing material such as chicken fencing or hog wire can be used to create a cage around an individual tree.  These materials are more expensive but many farms have them on hand, so they can be effective for smaller planting projects.

Fencing can be an option as well but are typically only financially viable for large, multi-acre projects and may be difficult to do in riparian areas.  It will take more time to install but generally requires less maintenance than tree tubes.  Fences should be a minimum of six feet high to prevent deer from jumping over.  In large open areas where deer have more space to jump, eight feet is recommended.  A “two-tiered” fence approach, where two shorter fence layers are staggered 4-5 feet apart (with an inner fence and outer fence), has also been successful at preventing deer from gaining enough speed to jump over fences.  If using fencing, be sure to provide an access point that is large enough for yourself and any equipment you will need to maintain the area. 

There are also “cultural control” methods of deterring animal damage.  This involves altering the environment to make the area inhospitable to pests.  For example, building next boxes and perches for large predatory birds can help reduce mice and vole populations when planting into grassy areas.  Similarly, reducing vegetation near trees will reduce cover for small pests.  “Dead wood fencing”, which involves creating a barrier with large woody debris (e.g. logging slash) throughout or around a planted area can help prevent deer and elk browse, which struggle to walk through that type of terrain.  Cultural methods are usually not sufficient to protect seedlings on their own but can be used to supplement other protective measures. 

Paired Planting w/ Spruce

“Pair planting” seedlings with Sitka spruce is a new strategy that some forest owners have used to help deter deer, elk, and small mammals from browsing on target seedlings like Douglas-fir or western redcedar.

In this method, Sitka spruce seedlings are planted in the same hole as the desired tree seedling. Sitka spruce needles are sharp and tough, which deters animals from feeding on the foliage. Since they have similar growth rates as other conifers, the spruce is often able to intermix with the foliage of the desired seedling and provide protection until it reaches a sufficient height to survive on its own. At that point, the spruce can be clipped at the base. Spruce seedlings are cheaper than many forms of tree protection, including tree tubes, so many forest owners that have tried it feel it pencils out economically. However, it is not known whether competition for moisture, sunlight, or nutrients from the spruce will slow the growth of desired seedlings.

Keep reading:

• Protecting Trees and Shrubs from Deer – USDA (PDF)
• Reducing Deer Browse Damage – USDA (PDF)

Maintenance

Good decision making, site preparation, and tree planting methods will go a long way to improve the survival rate of your planting project but maintenance will still be required over the next several years while they establish.  This can include, but is not limited to, moisture management, maintaining animal protection, back planting where trees didn’t survive, and adapting to new and unforeseen challenges.

Ensuring trees have water available for growth is very important for the first several years of a trees life while it establishes a sufficient root system.  This can be done by providing supplemental moisture through irrigation or by cultural methods that reduce moisture loss during the growing season.  Native tree species in our region have evolved to survive dry summers by completing most or all their annual growth in the spring to early summer.  However, this means that drought conditions during the spring can be particularly damaging to new plantings, especially if competing vegetation is present and reducing water availability.  Increasingly hot summers and an extension of the dry season will exacerbate that damage.  Your approach to moisture management for your seedlings will depend on the resources you have available and site conditions, specifically soil hydrology.  Irrigation can greatly increase the survival of tree seedlings during drought conditions but is not always necessary or feasible due to the cost and/or site logistics.  If using irrigation, drip irrigation methods are recommended to provide a slow moisture release into the soil.  Providing a layer of mulch within 1-2 feet of the tree will help reduce soil moisture loss as well as reduce the presence of competing vegetation.  Ideally, this would be done at the time of planting.  A 3-4” layer is ideal and should be arranged so that the area within an inch or two of the base of the tree is kept free of mulch to allow for air movement and avoid mold or fungal growth. 

In most cases, managing competing vegetation is an ongoing task.  Repeating the treatments you used during site preparation or utilizing different methods may be necessary to ensure weeds don’t outcompete the species you planted.  However, it’s not necessary to maintain bare earth.  Some vegetation is acceptable (and inevitable) but limiting the growth of vegetation within 1-2’ of the trees or shrubs you plant will improve their growth and ensure they are not overtopped by weeds.  Reducing vegetation around the trees can also keep that area exposed and reduce cover for pests like mice and voles. 

Maintaining your protection from animal damage will also likely take some time each year.  For tree tubes, it’s important to ensure that the tube covers the new growth by moving them up the tree one or two times in the growing season.  Fencing requires less annual maintenance but should still be monitored for gaps or damage allowing animals to enter.  As you maintain and monitor your planting, you may find that additional measures are required to protect your trees.

For most tree species, maintenance is only necessary in the first several years while the trees establish sufficient root systems and canopies to thrive on their own and develop some resilience to potential stressors.  Your new forest would be considered “free to grow” when you’ve reached a desired number of trees that have successfully established and grown tall enough that the leaders are no longer within reach of deer or elk browsing and cannot be overtopped by competing vegetation (typically 5-6’ tall).  For fast-growing species like red alder or black cottonwood (Populus trichocarpa), this can happen in as little as 2-3 years.  For conifers like western redcedar or Douglas-fir, this may take 5-6 years or more.  Animal protection can be removed at the free-to-grow point and vegetation management is typically unnecessary beyond this stage as the shade from the canopy will eventually eliminate weed growth, with the exception of shade tolerant weeds (e.g. English ivy, English holly, etc.) or when using a wide spacing that doesn’t support canopy closure. If you intend to graze livestock in the area, the free-to-grow point would also include the trees having sufficient diameter to handle potential rubbing or other damage associated with their presence, which may take a decade or more, depending on the species.

Monitoring is important during the establishment phase to keep watch for damage and mortality.  Finding one dead or damaged seedling is not a reason to panic, but it is worth keeping an eye on.  If mortality is significant, it may become necessary to spot fill areas where those trees died.  You will have to decide what your threshold for action is based on your objectives and available resources.  If you decide to replant in areas where mortality occurred, it’s important to do some diagnostic work first.  As discussed, animal browse, insufficient moisture, or competing vegetation can all be responsible for seedlings dying but insects, disease, and other environmental factors (e.g., frost, excessive heat) may also play a role.  Understanding what is causing the mortality will help you determine your approach for replanting and avoid repeating a mistake.  For instance, planting back the same species that was there previously may result in the same issue if the cause of mortality is related to unsuitable site conditions or a disease in the soil (e.g. root disease).  If you’re unable to diagnose the issue and mortality or damage is significant, seek advice from a technical assistance provider.  The WSU Puyallup Plant and Insect Diagnostic Laboratory also accepts photo submissions for diagnostic support but may require a fee. 

Keep Reading:

• Field Guide to Causes of Seedling Damage and Mortality in First Year Plantations – Industrial Forestry Association (PDF)

The work of maintaining a forest is never truly over, but once you reach “free to grow” the level of monitoring and maintenance required is significantly reduced.  Putting the proper effort up front will help you avoid failed plantings and financial losses.  For support with your project, visit the Technical Resources and Financial Resources pages to learn about programs that offer landowner assistance through site visits, planning and design, and cost-share.

Most beginning forest farmers will start by intensively managing a smaller area of the forest rather than installing a large-scale system, so small-scale assessments of microsites such as measuring shade and soils may be sufficient over broad forest assessments.  However, for people wanting to expand on an existing system or engage in practices like maple sugaring that require more forestland, assessing the whole forest will provide valuable information for long-term management and decision making.  A forest inventory will help you determine the structure and composition of your forest, which will inform the type and intensity of practices (e.g., thinning) required to provide ideal conditions for forest farming throughout the area.  Forest inventory includes multiple forest metrics such as tree size, density, species, and health, as well as other site conditions like shade and understory composition.  A consulting forester can provide a professional-grade inventory of a project area for a fee.  It’s particularly important to hire a forester if you’re interested in assessing the timber value of your forest (also called a “timber cruise).  However, a basic inventory can also be done by a landowner using some simple methods and inexpensive tools.  Web-based programs like LandMapper and PlotHound are also available to support your forest inventory.

A forest inventory relies on population sampling. Similar to how pollsters will ask a subsample of people how they feel about social issues or political candidates to gauge the larger population, a forest inventory measures randomly selected areas to create an informed vision of the whole forest.  There are many ways to go about this, but the simplest method is to randomly select points in the forest and establish circular “fixed” plots in which you can take your measurements.  The data you collect is then extrapolated to the whole area based on the size of those plots.   

A common plot size for small forest owners to use is a circle with a 16.7’ radius.  The area inside this circle is 1/50^th of an acre.  Using a measuring tape and a plot center, you can easily determine the perimeter of your plot at each randomly selected location.  You can elect to use a larger plot size.  For example, a 1/20^th acre plot has a radius of 26.3’ and will collect more data in those locations.  Doing more frequent, small plots is better for diverse forests while fewer large plots are suitable for more uniform forests (e.g. a Douglas-fir plantation). 

Plot Size (acres)	Radius (feet)
1/5	52.7 (52’8″)
1/10	37.2 (37’2″)
1/20	26.3 (26’4″)
1/30	21.5 (21’6″)
1/40	18.6 (18’7″)
1/50	16.7 (16’8″)
1/100	11.8 (11’10”)

Regardless of plot size and frequency, you will take the same measurements within the perimeter of each plot you create.  A forest inventory can consist of a wide variety of metrics depending on the site and objectives.  For forest farming, the most important measurements are listed below:

• Forest density describes how densely trees are arranged in a forest is most easily measured as trees per acre.  Forest density has significant impacts on forest health, shade, and tree growth.  It can easily be determined within a plot by counting the number of trees that fall inside the perimeter and multiplying it by the denominator of your plot size.  For example, if four trees fall within your 1/50^th acre plot, it would reflect 200 trees per acre (4 x 50 = 200).  What qualifies as a “tree” is typically determined by size and/or its’ position in the overstory.  Trees smaller than 3-4” in diameter are often ignored in a forest overstory assessment but for forest farming they might be included because they will still impact shade levels.
• Shade describes the amount of light hitting the forest floor and will have significant impacts on most forest farming operations.  It’s typically described as a percentage and is the inverse of light availability.  Shade should be determined at each plot location, which can be done with a densiometer or through the paper plate method described in the site assessment section.
• Tree size is described as diameter and is measured by using a measuring tape to wrap around the circumference of the tree.  This metric helps you understand the average size of trees in the forest and how they vary with species, which can help you determine a thinning prescription if necessary.  This can be easily done using a cloth measuring tape and then dividing the number by pi (3.14) to get diameter.  However, a diameter tape can be worth investing in, which has the value of the pi incorporated on the tape and eliminates the need for any math.  Regardless of the tool used, diameter should be taken at “breast height”, which is standardized to 4.5’ off the ground for consistency.  Determine and record diameter for each tree inside your plot.
• Species is also important to record inside your plots for each tree.  This will allow you to figure out how metrics like diameter vary between species. The relative frequency of species will also help you determine dominant type of shade (e.g. conifer versus hardwood). 
• Understory vegetation is worth assessing given you may either be tending existing populations of understory crops or establishing other plants.  Understory plants are also often some of the best indicator species and can help you better understand your site.  A rough “eye assessment” is usually sufficient and can be as simple as recording what is present, and possibly including the relative composition (e.g. 20% sword fern, 10% salal, etc.). Noting the presence of invasive species like Himalayan blackberry or English ivy can also be valuable for your management. 

The following are optional metrics that may or may not be useful to include in your forest inventory:

• Tree height may be valuable to better understand the structural composition of the forest.  However, it can be more difficult to determine accurately without investing in forestry tools.  A forestry stick (also called a “Biltmore stick”) can give you a rough estimate for height.  These are cheap to buy and it’s also possible to make one yourself.  Clinometers or rangefinders will give you more accurate measurements but are much more expensive.  Since the process is a bit cumbersome, heights are often only taken for one tree (randomly selected) within the plot.
• Tree cores can provide good data but similarly require investment in specialized forestry equipment.  Tree cores can provide two valuable pieces of information: age and growth rate.  A tree core is taken using an increment borer, which is a specialized hollow drill bit that is manually drilled into the center of the tree perpendicular to the growth rings.  The result is a small cylindrical subsample of the wood that allows you to count the number of growth rings to determine age.  Age can be helpful to understand where a tree is in its lifespan and what to expect in the future.  Red alder, for instance, only lives to be 60-80 years old and often starts to decay as early as fifty years old.  The growth rate of trees can be determined by examining the relative size of the growth rings.  It’s common to see more narrow growth rings occur because of increased competition from surrounding trees, which indicates the need for thinning.  Similar to heights, this process can be time consuming is often only done for one tree per plot.
• Tree health can also be very valuable to assess while you’re completing your plots.  Determining if a tree is suffering from a pest, disease, or other stressor may help you decide if you want to keep it in favor of retaining healthier trees.  Pockets of root disease, for example, are great spaces to create small gaps where more sunlight can penetrate and allow you to cultivate species that produce better with higher light availability (e.g. thimbleberry, hazelnut).  To better understand and evaluate tree health, read the WSU Extension Publication “Assessing Tree Health”.  Additional resources are available at the end of this section.

Once you’ve collected your data, interpreting it for forest farming applications can be straightforward as well.  However, a technical assistance provider will be able to use their experience to better translate that information to land management and/or help you with the inventory itself.  For more information on technical assistance available to you, visit the Additional Resources page. 

If doing it yourself, start by averaging some of the data across all your plots. Averaging is done by adding up the individual numbers then dividing by the number of data points.  For instance, if you did four plots and the shade levels were 90%, 80%, 90%, and 70% shade, simply add those together and divide by four to get 82.5% shade for the forest.   Average density (trees per acre) can be done the same way, remembering that you must first get trees per acre value in each plot by multiplying the total number of trees in the plot by the acreage represented in your plots (e.g. for a 1/50^th acre plot, multiply by 50). 

Diameter should be averaged by species to determine how they differ in size.  Determining relative species composition is a little trickier.  You do this by first determining the number of times each species occurs in the plots, averaging them, and then multiplying by plot size to determine the number of trees per acre it represents.  For instance, if you had four 1/50^th acre plots and red alder was present twice in the first plot, once in the second plot, none in the third plot, and twice in the fourth plot, average those numbers (2+1+0+2 = 5, then 5/4 = 1.2) to determine that red alder occurs 1.2 times every 1/50^th acre.  This means that there are an estimated 60 red alder trees per acre across your forest (because 1.2 x 50 = 60).  Do this for each species to determine their relative population in the forest. 

Using the data you collected on shade percentage and total tree density will help you determine if you need to reduce density or take other actions to meet your forest farming needs.  This, combined with the numbers you determined for average size and relative density of species will help you develop a course of action (discussed in the Thinning section). 

Some landowners may prefer to skip the inventory step and simply “eye” it.  For small projects (less than an acre) or for people that have significant experience thinning forests, this may be a viable option.  However, if you are working larger acreages and/or don’t have experience with forest management, knowing the forest you’re working in before getting started can be immensely helpful.  Remember, you can’t put trees back on the stump!

Keep Reading:

• Assessing Tree Health – WSU Extension
• Basic Forest Inventory Techniques for Family Forest Owners – WSU Extension
• Forest Health and Management – OSU Extension
• LandMapper
• Making a Biltmore Stick – Alabama Extension (Video)
• Simple Homemade Forestry Tools for Resource Inventories – WSU Extension

Thinning

Thinning is a forest management practice by which trees in a stand are strategically selected for removal to benefit the growth of remaining trees, as well as forest health and function.  In the context of forest farming, thinning is often applied to increase the amount of sunlight reaching the forest floor.  The intensity of thinning will be determined by the shade and light requirements of your desired crops and density of the existing canopy (see the Forest Inventory section and the Site Assessment section for more information on assessing existing shade conditions).  Thinning will not always be required to establish a forest farming system or, in the case of small projects, may be as simple as removing 1-2 trees.  However, as forests are in a state of constant growth and change, understanding thinning as a tool to maintain ideal light conditions is an important part of being a forest farmer.

There are several different approaches to thinning.  The three types described below are common forms used in the Pacific Northwest and methods with special application to forest farming.

• Thinning from below is the most common form of thinning in our region, especially in conifer plantations.  Smaller and poorly formed trees are removed from the canopy to achieve an ideal tree density and leave behind the best performing trees.  The removal of trees reallocates resources to those remaining while leaving a relatively high stocking rate for harvesting. This type of thinning supports vigorous growth and timber production.  For forest farming, thinning from below is ideal for supporting existing overstory trees and retaining denser shade conditions for crops that require it like ginseng or wasabi (Burkhart, 2024; Miles & Daniels, 2019). 

• Thinning from above is a much less common form of thinning in the Pacific Northwest, but is common to hardwood forests in the eastern U.S.  It is the inverse of thinning from below, which means trees that are dominant or co-dominant in the canopy are harvested to “release” or support the growth of species growing in the understory.  This practice might be applied when the species comprising the overstory are less desirable and a forest owner wants to support shade tolerant trees growing below to recruit into the overstory.  An example of this in Western Washington would be thinning out a decaying red alder stand to release western redcedar or western hemlock growing in the understory.  Thinning from above can be a useful tool for forest farmers where they want to grow crops that yield better under higher light conditions, such as elderberry or huckleberry.  However, opening the canopy too much can allow noxious weeds to get established (e.g. Himalayan blackberry).  Historically, thinning from above has been distorted and used as an excuse to harvest the most valuable trees in the overstory while leaving behind low-value trees (also called “high-grading”).  This practice can negatively impact forests for decades and should not be considered an option for sustainable forest management.
• Variable density thinning (VDT) is a mixed approach with the goal of increasing structural and species diversity in a forest that lacks those characteristics (Bekris et al., 2021). “Skips” and “gaps” are created to produce heterogeneous tree cover.  Skips are areas that are left unthinned and relatively dense, while gaps are small areas where all trees are harvested.  The spaces between these are thinned to a variety of target densities. This diversifies forest structure, which in turn benefits forest functions like wildlife habitat.  From a forest farming perspective, these mixed light conditions can be planned and utilized to grow a variety of crops.  For instance, gaps are excellent spaces for growing trees and shrubs that yield better under higher light conditions and/or creating “food forests” that can sustain multiple crop species.

Regardless of approach, thinning to reach a target density and shade level for forest farming can be difficult to do on your own if you have limited experience with forest management, especially for larger projects.  A skilled forester can assess the density of your existing stand and then write a thinning prescription for hitting a target density.  They can also mark trees for removal that will help meet those light conditions and your other desired objectives.  If you’re thinning project includes targetting large trees with commercial timber value, a forester can navigate a timber sale for you and are often able to negotiate better prices for the logs you sell.  This will help you mitigate costs associated with thinning operation, or perhaps turn a profit.  If your project requires thinning large, commercially valuable trees but the size of the job is not large enough to attract a logger, you may still consider hiring a skilled tree feller to do the work (especially if you are not experienced in felling large trees).  This will reduce risk of injury to yourself and mitigate damage to the remaining trees in the forest.  Small-scale sawmill operators are available to mill logs into lumber you can use on site or sell.  Some also offer tree felling services.

The ideal shade level will depend on the species you intend to grow in the understory but is generally between 60-80% shade for most forest farming crops (Bardhan & Kronenberg, n.d.), remembering also that for spring ephemerals like ramps, the timing of shade is equally as important as density.  Thorougly research the crop you’re interested in growing to understand it’s light demands prior to thinning.  Recognize too that some species can establish and grow in shade, but are unlikely to yield well in those conditions and are therefore not ideal for forest farming in riparian forests. For instance, berry-producing species like osoberry or evergreen huckleberry often grow in 60-80% shade, but their berry yields will be significantly limited by the lack of light.  If you’re only growing for personal consumption, this may not be an issue but it is not likely to be sufficient for forest farmers with interests in commercial production.  Higher light levels are needed to provide sufficient yields in many berry producing species, which is not conducive to riparian forests where canopy closure is important for habitat.  However, crops like these can be grown at smaller scales in small forest gaps within buffers and along forest edges where more light is available, or in the outer zone of a buffer where reduced canopy cover will have a limited effect on riparian habitat.

Translating an ideal shade level to a target tree density (trees per acre) can be challenging, but will help you develop a strategy for thinning.  In relatively uniform stands where trees are mostly the same species, age, and size, reducing shade level can be done in proportion to the existing tree density.  For example, reducing a Douglas-fir plantation with 90% shade and 300 trees per acre to 60% shade can be as simple as removing a third of the trees down to 200 trees per acre. In diverse forests comprised of trees of a variety of species and sizes, the relative density and proportion of shade contributed will vary from tree to tree.  This requires more finesse in your thinning, and relying more heavily on the species distribution data you collected in your forest inventory. 

For instance, if your data shows that there is a significant portion of old (50+ years) red alder trees in your forest, you may target those trees first as they have short lifespans and won’t provide long-term shade.  They also have smaller, less dense canopies that would allow you to “fine tune” the shade level in the understory with their removal.  Of course, you have to weigh targetting a species for reducing shade against your desire to retain them on site for other purposes such as a crop they can produce (e.g. syrup, boughs), potential habitat benefits, or whether the type or timing of shade they provide is valuable (i.e. seasonal versus yearround). 

For very small understory forest farming plots dealing with microsites (< 0.5 acres), an inventory and thinning prescription are likely overkill and a landowner may decide to simply “eye it”.  However, understanding the concepts for managing larger areas will still be valuable for small projects.  If using the “eye it” approach, be sure to remove trees slowly and check the shade level in the area you intend to install your plot after each tree to see how you are approaching your target.  Start with smaller, suppressed trees and shrubs rather than going directly to felling larger trees (unless your objective is to create a small canopy gap).  Thinning on a sunny day while the leaves are on the trees (in the case of deciduous trees) will be important for tracking your progress. Perfection is not the goal with thinning for forest farming.  Even with the most meticulous work shade levels will continue to vary.  So, simply shoot for achieving a range or average for your whole project area. 

Although not discussed here, keep in mind that some state and local regulations may restrict your ability to thin within a certain distance of a stream or other riparian feature.  The type and intensity of restrictions will depend on the characteristics of the stream, such as whether it is season or non-seasonal and whether it is fish-bearing.  For more information, see the Regulations section of the Additional Resources page. 

Pruning

Pruning will have a more limited effect on shade than thinning and is good for “fine-tuning” the amount of light hitting the forest floor.  Depending on the composition of your forest, it may or may not be necessary, or even an option, for altering shade levels. Most shade-intolerant trees (e.g. red alder, Douglas-fir) are good at self-pruning lower limbs when there is sufficient competition for light from nearby trees.  Shade tolerant species (e.g. western redcedar, western hemlock) tend to retain lower branches longer and may require pruning when used as cover for forest farming. 

Pruning will have a more limited effect on shade than thinning and is good for “fine-tuning” the amount of light hitting the forest floor.  Depending on the composition of your forest, it may or may not be necessary, or even an option, for altering shade levels. Most shade-intolerant trees (e.g. red alder, Douglas-fir) are good at self-pruning lower limbs when there is sufficient competition for light from nearby trees.  Shade tolerant species (e.g. western redcedar, western hemlock) tend to retain lower branches longer and may require pruning when used as cover for forest farming. 

Pruning is best done while trees are dormant, between November and March, to reduce the risk of spreading pests and disease and minimize damage to the bark.  However, it’s difficult to determine shade impacts of pruning on deciduous trees in the winter, so it may be necessary to do it during the growing season.  In this case, target late summer to early fall (late August to October) as trees are beginning to go into dormancy at that time.  When pruning, never remove more than 30-50% of the canopy in a year. 

Pruning trees also produces higher quality timber products.  It is especially important when growing high-value products like veneer.  Limbs that grow larger than 2-3” will decrease wood quality. Harvesting and selling timber is subject to restrictions within a certain distance of streams and other features, depending on the stream size and type.  Refer to the Washington Department of Natural Resources Forest Practices Illustrated Guide to learn more.

Keep Reading:

• Conifer Pruning Basics For Family Forest Owners – WSU Extension
• Pruning Forest Trees – University of Missouri
• Forest Practices Illustrated – WA DNR

When establishing a forest farming operation in lower density forests, existing canopy gaps, and hardwood-dominant forests, site preparation to eliminate existing understory vegetation will likely be required.  Generally, site preparation in an existing forest will be less intensive than what is required in afforestation contexts due to shade limiting vegetation growth.  The same options described in the “Planting a Forest for Forest Farming” section are available but may be applied differently in this context.  The most appropriate method will depend on existing vegetation, site conditions and your available resources.  Integrated pest management (IPM) is strongly recommended, which is a strategy that utilizes multiple approaches to managing unwanted vegetation efficiently and with limited ecological impacts. 

Hand pulling and removal is a feasible strategy for eliminating existing vegetation when the project area is small, there is limited existing vegetation to deal with, or if you have help available to provide additional labor.  This method limits soil disturbance and chemical inputs.  Herbaceous species can often be uprooted by hand or with the help of hand tools.  Woody perennials and shrubs can be cut at the base but may come back (depending on the species).  Hand-cutting and a “cut stump” herbicide treatment can be very effective for removing woody perennials.  However, their removal is not always necessary, especially if the shade they provide is valuable. In some cases, simply raking back leaf and woody debris is sufficient to establish forest farming plots.

Chemical applications can be used to eliminate competing vegetation efficiently and effectively.  Most herbicides are used to treat existing vegetation, but pre-emergent herbicides are also available, which prevent seed from sprouting.  The use of herbicides in or near riparian areas should be limited wherever possible but are an effective strategy for removing vegetation during site preparation.  They are particularly suitable to large projects where other methods are not financially viable.  When using herbicides, always read the label and be aware that some have limited legal applications within certain distance of water and/or require special licensing. For recommendations on chemical applications for specific weed species, refer to the PNW Weed Management Handbook. 

Sheet mulching, also referred to as “lasagna composting”, involves layering organic materials (typically 3-6” thick) over an area you intend to plant.  This eliminates existing vegetation prior to planting and will continue to suppress vegetation while your crop species are getting established.  Mulching utilizes materials like cardboard and woodchips, which can often be sourced for free or with limited cost and add organic matter to the soil over time.  However, it may add labor to the planting process, especially if you must cut through layers of cardboard to get to the soil for planting.  While mulch can effectively mitigate soil moisture loss through evaporation, it can also reduce soil recharge from rainwater. Sheet mulch is also susceptible to being washed away in areas that flood, so it’s important that you know where flooding may occur on your site to determine where other strategies are more appropriate.  Mulching pairs well with raised forest beds (see “Designing a Forest Farm” section), which involves bringing in supplemental soil or compost to create better growing conditions for crops.  Establishing a layer of mulch below the raised bed will reduce unwanted vegetation from growing in them. 

Keep Reading: 

• Sheet Mulching:  A Quick Guide to Getting Started – Pierce County Conservation District (PDF)

Solarization is the process of laying clear plastic over a project site to destroy existing vegetation.  The plastic covering creates a greenhouse effect, trapping heat and moisture, that kills the plants underneath.   This is best done during the growing season to take advantage of warm, sunny days.  Depending on the weather, solarization may take 2-3 weeks to effectively kill the vegetation beneath.  Occultation is a similar practice, but instead uses opaque materials (e.g. black plastic tarp).  Because the material is opaque the greenhouse effect is limited, and the process takes longer (often 3-6 weeks) but landowners are more likely to have these materials already so it can be the more cost-effective option.  These practices may have limited application in forest farming settings given the reduced light availability on the forest floor.  However, they may still be effective at eliminating existing vegetation when working in canopy gaps or low shade conditions (50% or less), but the process will take longer. Solarization and occultation will control vegetation prior to planting but are not recommended for controlling vegetation afterwards because their heating effect on the soil may damage crop roots.   Although research is limited on this practice, it may have the benefit of killing harmful organisms in the soil, but it will also destroy beneficial organisms.  Using an arbuscular mycorrhizal inoculant on the roots of plants during planting may help offset any negative effects solarization or occupation has had on beneficial soil biota. 

Keep Reading:

• Using the Sun to Kill Weeds – University of Minnesota Extension

• Soil Solarization: An alternative to soil fumigants – Colorado State University Extension

Tilling is a mechanical site preparation strategy that involves ripping or turning over soil in the areas you intend to plant.  This kills existing vegetation and makes soil more workable for planting.  Generally, tilling is most appropriate when working in an alley cropping arrangement where the trees being arranged in rows make it easier to avoid damage to roots but it can also be done in natural forest settings in a more limited scope.  To limit damage to trees and soil, use hand tools or small equipment (e.g. roto-tiller) and reduce tilling depth to not more than 2-3”.  Avoid tilling on slopes that will result increased sediment deposits into waterways. 

Minimizing disturbance and inputs is a priority in riparian habitats.  In some cases, it may be feasible to establish a forest farming operation while working around existing native vegetation in the understory, especially if they provide beneficial shade, additional crops for personal use or sale, or beneficial interactions between species.  For instance, Oregon grape produces berberine in its roots, which has anti-fungal properties that may benefit the health of adjacent crops.  It also produces berries, decorative foliage, and medicinal products. 

Non-native, invasive weeds, however, should always be removed ahead of establishing a forest farming system.  Shade tolerant noxious weeds like English holly, English ivy, and yellow archangel will continue growing in low-light conditions and outcompete crop species.  In forest stands with higher light availability, less shade tolerant weeds like Himalayan blackberry or Scotch broom may get established and compete with crops in your forest plots.  This can also occur after thinning. Thinning, site preparation, and planting of crop species should be timed in succession to reduce the presence of unwanted vegetation establishing in the interim.   Managing noxious weeds and other unwanted vegetation will require ongoing monitoring and maintenance beyond just site preparation.

There are multiple approaches to forest farming in the understory, which are influenced by the intensity of management you have capacity and interest to apply:

• Wild stewarding is the least intensive form of understory cultivation.  In this approach, a landowner or manager will identify crop trees, plants, or fungi that are already growing on site for harvest (Rural Action, 2019).  The existing population is tended and expanded to sustain yields over multiple years.  This approach may also include managing unwanted vegetation to promote the growth of target species and limited thinning or pruning to create desired light conditions.  Wild stewardship is the lowest risk approach due to limited inputs but will result in reduced production compared to other approaches. Because of it’s low inputs and footprint, it can also be practiced in the inner zone of a riparian buffer.
• Wild simulated is a more intensive forest farming method that includes establishing a species on a site that did not exist there previously (Rural Action, 2019).  Crops selected for wild simulated systems will be native species that are suited to the site’s conditions or non-native plants that grow in analogous conditions.  This approach will likely require more inputs, including site preparation, thinning, pruning, and/or animal protection (i.e. fencing).  Limited chemical inputs or soil amendments may be used.  Wild simulation is effective at efficiently producing crops for markets that desire crops with “wild” characteristics (University of Missouri, 2018).
• Woods cultivated is the final and most intensive approach to forest farming.  In woods cultivated systems, there are significant inputs of time and materials to maximize yields of forest crops.  This can include establishing raised beds and significant soil amendments, as well as site preparation, intensive thinning, pesticide applications, and fencing. Woods cultivated systems generally focus on a smaller number of crops than to cultivate them more efficiently.

Some forest farming practices don’t fit nicely into these classifications. For instance, maple sugaring is arguably the most well-known and widespread form of forest farming in North America and supports a billion-dollar industry in the U.S. alone. However, it doesn’t fit neatly into any of the three forest farming categories. It would most likely be lumped in with woods cultivated sheerly due to the high inputs required, but it’s an exception that highlights the flexibility of forest farming and agroforestry more broadly. For existing or budding forest farmers, it’s important not to get too hung up on these and other classifications but to instead use them as a tool for planning and developing a better understanding the practice. 

Overstory

The canopy is what makes a forest a forest.  Up until now we have largely discussed the canopy in the context of the shade it provides. However, canopy trees can be selected and managed to produce valuable crops while still allowing for understory cultivation.  Tree syrups are a great example of a product derived from overstory trees.  In fact, maple sugaring is the most common form of forest farming in North America.  In the Pacific Northwest, tree syrups are a less established forest product than in regions like the Midwest or Northeast, where syrup is frequently made from sugar maple (Acer saccharum).  However, significant effort and headway has been made to support the development of a maple sugaring industry in western Washington and Oregon using our native bigleaf maple (Acer macrophyllum).  For more information on this, see the bigleaf maple syrup crop profile.  Paper birch (Betula papyrifera) is another native species that can be used to make syrup.  Both birch and maple are well suited to riparian sites and forested buffers.  There is also some evidence that red alder sap can be harvested when using artificial vacuum, but information is limited on this. 

Other crops derived from overstory trees includes boughs, pinecones, and edible crops like fruits, nuts, and flowers.  Boughs from western redcedar trees are a common non-timber forest product in the Pacific Northwest.  They are used for floral arrangements, wreaths, and other holiday decorations.  Indigenous communities also use western redcedar bark for a wide variety of products, including clothes, basketry, and cordage.  Pinecones can be harvested from native western white pine and Ponderosa pine, also to be used for decorative products.  Ponderosa pine nuts are also edible. Oregon white oak acorns were historically cultivated and processed for flour by indigenous communities.  Bigleaf maple flowers can be harvested in the spring and are a delicious addition to salads or can be fried and/or pickled.  Non-native fruit and nut producing species with better developed markets (e.g. chestnut, walnut, persimmon) can be a component of forest farming systems too, but are best relegated to the outer zones of working riparian buffers to ensure mostly native species in the inner zone.

Midstory

The space between the understory and the overstory is called the “midstory”.  The exact boundary of the midstory can vary but the term is generally used to refer to woody shrubs and smaller trees that grow above understory vegetation but do not have the growth traits to reach recruitment into the canopy. Shade tolerant canopy trees like western redcedar and bigleaf maple will also occupy the midstory temporarily while they grow into the overstory.

The midstory is an ideal space for native fruit and berry producing shrubs like currants, elderberry, hazelnut, and huckleberry.  Non-native shrubs and commercial cultivars of native species can also be grown in the midstory.  Although many of these species will establish and yield under shade, those yields will often be limited.  Most species will yield better with greater light availability, which could be achieved by cultivating them in a canopy gap or planting them along a forest edge.  

The midstory is also a good place for fiber and decorative crops like willow.  Willow “whips”, small diameter stems, are grown, harvested, and weaved to make baskets.  Decorative species like pussy willow produce attractive flowers and brightly colored stems for floral arrangements.  Cottonwood species can also be used for baskets, and the buds can be collected and processed into medicinal products.  These species are both suited for riparian soils and can be “coppice” managed to continuously produce smaller stems. 

Understory

Growing crops in the understory is what is most often referred to when using the term forest farming.  This typically involves growing herbaceous food, medicinal, or nursery crops on the ground below a forest canopy.  Examples of high-value understory crops that are commonly forest farmed include ramps, ginseng, goldenseal, and black or blue cohosh.  These species are not native to Washington State but could be grown in analogous conditions here.  Since these crops already have established markets, they have high potential as additions to farming enterprises and small forest ownerships.  WSU Extension researchers are currently examining multiple crops, including log-grown shiitake mushrooms, ramps, ginseng, tea plant, and wasabi for production in forested settings.  As this information becomes available, it will be posted on the Crop Profiles page.

The market for wild foraged mushrooms (e.g. chanterelles, oysters, truffles) is significant and well-established in the Pacific Northwest.  Most of these are difficult to reliably cultivate in commercial quantities in forested settings but wild stewarded and wild simulated approaches could yield enough for personal use.  One exception to this is shiitake mushrooms, which yield reliably in forest cultivated systems in Western Washington and are an excellent addition to farming enterprises.  Additionally, several institutions are researching best management practices for commercial cultivation of native truffle species in Pacific Northwest forests.  Truffles are high-value mushrooms prized for their culinary applications.

The market for decorative greenery harvested from forests (e.g. salal, beargrass, sword fern) is also significant in the Pacific Northwest.  Greenery can be cultivated relatively easily but has limited return on investment because of their relatively low market value.  Many small forest owners sell greenery and boughs from their forests for supplemental income between timber harvests.  However, most of the market needs are met by collection on large private ownerships (i.e. timber industry) and public lands.  Wild stewarding practices are most applicable for decorative greenery because of the low return on investment. Native nursery stock and seed can also be cultivated in the understory of forests, and the market for native plants is arguably one of the better developed for forest farming crops in the Pacific Northwest.  Although they are typically not high-value products, selling potted plants and shrubs or seed can be a viable source of supplemental income with limited inputs. 

Value-added products can be a great way to increase the value of crops harvested from forest farming operations.  Wild jams and jellies, decorative wreaths, and essential oils are all examples of value-added products derived from non-timber forest products.  Marketing these products as “wild”, “forest-grown”, and locally produced can further increase their value.  Keep in mind that processing food products will be subject to state and local regulations and licensing requirements.

Markets for most forest farming crops are underdeveloped in the Pacific Northwest, particularly native species.  Non-native crops with existing markets, such as ramps, shiitake, or wasabi, may be the best points of entry for beginning forest farmers, while electing to expand and diversify to less explored crops over time.  There are many native species with potential to produce commercially viable food, medicine, or decorative products, but need more market development.  For example, Oregon grape contains berberine, the active compound found in goldenseal, which is a high-value forest farming crop in the eastern U.S.  Oregon grape growers in the Pacific Northwest can market Oregon grape products as a potential substitute for goldenseal. There is also significant opportunity to learn from and support traditional ecological knowledge (TEK) about the use and management of non-timber forest products from indigenous communities. 

The forest is home to all types of hungry mammals, birds, insects, and more.  Naturally, this can result in pest pressure on crops in your forest forming plots.  The type of pests and mitigation strategies will vary greatly depending on the crop.  For instance, log-grown shiitake and ramps are frequently targeted by slugs.  Deterrents for these pests can include slug bait traps, slug killer products, copper or metal mesh barriers, and, in the case of shiitake, wrapping logs in fruiting blankets.  For understory and midstory crops growing in the ground, fencing may be the most practical solution to prevent herbivory from small and large mammals (e.g., “deerbuster” fence).  Some forest farmers will use trees as supports for fencing to cut down on costs.  Others have piled up downed wood to create a debris fence.  For berry and nut producing crops, netting or other bird deterrent strategies may be necessary.  The inputs to protect an operation will be scaled with the intensity of management and your desired yield.  Some may be content to “share” with the wildlife and take what is available to them for personal use.  Wild stewarded and wild simulated systems may take the approach of planting excess to factor in potential pest-related losses or other low-budget solutions.  However, woods cultivated systems would merit a greater investment in pest mitigation efforts to protect assets.   

“Floating Block” Fencing

Fencing can be expensive, so creative solutions can be a key to saving time and money.  A relatively cheap way to prevent browse from deer and other large mammals on forest farming crops is “floating block” fencing.  With this method, high tensile wire is wrapped around the perimeter of an area where crops are being grown, using trees as supports.  Once the wire is tensioned, deer fence (typically 7-8’ tall) can be attached to the wire.  You should have at least two wires, one along the top and bottom.  A middle wire can provide extra support, especially if you’re dealing with pressure from large animals like elk.   When setting up the wire, cut small sections of a rigid plastic tubing where the wire comes in contact with trees to protect them from the tension (see photo).  Leaving a “skirt” of fencing along the bottom and staking it to the ground or partially burying it can help prevent smaller animals from getting in.

Using this method, fencing can cost between $1.40-$2.00 per foot (based on 2025 prices). In the photos below, the area protected is approximately 2,500 square feet and was done for less than $300.

Cost break-down for 2,500 square foot plot (~0.06 acres):

• Deerbuster fencing (8′) – $1.30 per foot ($234 total)*
• 12.5 gauge high tensile wire – $0.05 per foot ($9 total) *
• Fencing strainers and tensioner tool – $15
• Zip ties to connect fencing to wire – $21
• Total: $279

Using those prices, the cost for fencing a half-acre with this method would be ~$780 and a full acre would be ~$1,100.

*Typically bought in bulk. Prices and minimum amount will vary.

Of course, animals are not the only pests to consider when protecting crops.  Poaching is a common problem in forest farming operations in the eastern U.S. where high-value crops like ginseng and goldenseal are grown.  Poaching is also an issue the Pacific Northwest, particularly for timber as well as some non-timber forest products like cedar boughs or figured maple wood.  Developing a strategy for mitigating exposure to poachers is worthwhile when designing and maintaining a forest farming operation regardless of region. See “Accessibility” in the Site Assessment section for tips on preventing poaching of your forest farming crops.

Forests are not static.  Just as trees grow and develop, forests change too. Although these changes are typically not noticeable year to year, over decades the structure and composition of a forest will evolve to completely change how the forest looks, potentially affecting what crops can be grown there. 

Forest development refers to the structural changes in forests over time.  These changes will be most noticeable in the first several decades of a forest’s lifespan.  Forest development consists of four stages, also called “seres”:

1. Stand initiation – whether by planting or through natural regeneration, this stage includes the establishment of a new “cohort” of trees after a large-scale disturbance (e.g. harvest, wildfire).  This stage has the highest tree density.
2. Stem exclusion – The high density of trees established during stand initiation leads to canopy closure and heavy competition for light and other resources.  This leads to significant mortality.  Native pests and diseases (e.g. bark beetles, root diseases) are often found in greater populations at this stage but also help facilitate the stand to “self-thin”.
3. Maturity – After the period of high competition and mortality, the forest experiences a long period of relatively low competition and mortality among the original cohort of trees.  Meanwhile, shade tolerant species establish and grow in the understory and midstory.
4. Old growth – After decades or centuries of growth, the original cohort of trees in the overstory begins to die off, leaving canopy gaps for shade tolerant species to take over.  Large standing trees and large down wood are signatures of old growth forests, along with a spectrum of age classes among trees.

In the Pacific Northwest, a forest can reach maturity in 80-100 years, while old growth typically takes centuries to achieve.  Forest farming can occur at any stage, but most small private forests will be somewhere between stand initiation and maturity.  Working with forest development to maintain suitable structure for forest farming requires proactive management through thinning and pruning to create ideal light and shade conditions. 

Succession refers to changes in forest composition over time.  Typically, the first cohort of trees established during stand initiation are shade intolerant species that grow well on disturbed sites with bare mineral soil.  These are referred to as “pioneer species”.  In Western Washington, examples of these species are red alder, Douglas fir, cottonwood, and Ponderosa pine.  As the forest develops, shade tolerant species establish in the understory (e.g., western redcedar, bigleaf maple, western hemlock) and eventually recruit into the canopy as gaps open.  As previously discussed, the composition of a forest overstory will dictate the density and timing of shade, which will impact understory and midstory crops.  Thinning and pruning can help manipulate shade, but other tools like understory planting and coppice management can help dictate the species composition in favor of your forest farming operation for years to come.

For many, these changes will not significantly affect operations in their lifetime but should still be considered in their management to sustain operations over multiple generations (if that is the goal).  Still, some people may be establishing forest farming systems at key transition points in a forest’s development and must consider these dynamics.  For example, many small forest owners in Western Washington own decadent red alder stands.  Red alder is short-lived and begins to decay as early as 50-60 years old, rarely living past 80.  These stands often naturally transition to western redcedar or western hemlock, which will drastically change conditions for forest farming.  Alternatively, if there is not sufficient seed source for shade tolerant conifers nearby, the increasing light availability as the red alder dies off facilitates noxious weeds like blackberry to take over.   Landowners facing this situation will need to proactively manage for desired future conditions by planting desired trees in the understory to maintain the forest canopy and their forest farming operation.  For help with this specific situation, see the WSU Extension Publication “Management Options for Declining Red Alder Forests”.

Disturbance is a natural part of forest development.  This refers to any biotic or abiotic factor that damages or kills forest vegetation, particularly overstory trees.  Understanding the factors that can affect the health of the flora that comprise a forest is key to operating a forest farming system long term.  This includes animal damage, insects, disease, wildfire, and, more broadly, a changing climate.  These can impact forests at any stage of development and require an understanding of local and regional forest health issues to prevent potential damage to a forest farming system. 

Animal damage is most problematic during forest establishment, but some animals can cause damage in more established forests.  Examples include deer or elk damaging bark while rubbing antlers (i.e. “buck rub”), beaver felling trees for habitat, or black bear removing bark to feed on sugar-rich plant tissue in the spring.  In most cases, this kind of damage does not occur at a scale that warrants management.  If it does, strategies to mitigate damage can include trapping, hunting, and installing fencing or other animal deterrents.   It is important to consult with local, state, and federal wildlife restrictions or contact your state’s wildlife agency before trapping or hunting. 

Insects and disease can affect trees of any size or age.  Problems with native pests are often caused by poor growing conditions which inhibit trees’ abilities to defend themselves. Proper species and site selection can prevent these issues as well as proactive thinning to manage stand density and ensure remaining trees have proper light, water, and nutrients to maintain vigorous growth.  The more worrisome insects and diseases are non-native and can significantly damage or kill healthy trees.  Examples of this include emerald ash borer (Agrilus planipennis), Asian long-horned beetle (Anoplophora glabripennis), and sudden oak death (Phytophthora ramorum), all of which cause widespread tree mortality.  Knowing which invasive pests are present or expected in your area will influence your species selection and forest management decisions.

Wildfire also has significant impacts of forest health and structure.  Forest fires have become particularly widespread and intense in the interior of the Pacific Northwest, but fire also plays a role in the forest ecology of Western Washington. For forest farmers in fire-prone regions, protecting crops from wildfire is critical and may require practices like fuel load reductions, thinning, pruning, and installing fire breaks.  Alternatively, some forest farming operations may include opportunities to utilize fire as a management tool.  Camas (Camassia quamash (Pursh) Greene)), for example, functions well within a frequent fire ecosystem (e.g. oak/camas prairie) and can benefit from prescribed burns. 

Climate change will have significant impacts on forest health and composition throughout the U.S. in the coming decades.  Individuals creating a new forest have an opportunity to improve their climate resilience by planting trees that are likely to adapt to future conditions.  This could mean choosing species that are resistant to drought and severe weather or transferring plant genetics from southern regions (i.e. seed zone transfer) to help trees adapt to warmer climate.  In established forests, applying silvicultural practices like thinning to ensure sufficient light, water, and nutrients are available to overstory trees can help build resilience, as well as harvesting and planting to select more resilient species.

Keep Reading:

• Assisted Migration – USDA Northern Climate Hub
• Assessing Tree Health – WSU Extension
• Backyard Forest Stewardship in Eastern Washington (PDF) – WSU Extension
• Backyard Forest Stewardship in Western Washington (PDF) – WSU Extension
• Climate Impacts in the Northwest – USDA Northwest Climate Hub
• Climate Resilience Guides For Small Forest Landowners (Western Washington/Eastern Washington) – USDA Northwest Climate Hub
• Forest Ecology in Washington – WSU Extension
• Forest Health Highlights – Washington Department of Natural Resources
• Forest Health and Management – OSU Extension
• Landowner Assistance Portal – Washington DNR
• Managing Douglas-fir-western hemlock forests of the Coast Range and Western Cascades with fire in mind – OSU Extension
• Management Options for Declining Red Alder Forests – WSU Extension
• Silviculture for Washington Family Forests – WSU Extension

For more resources on forest management, visit the Resources page of the WSU Extension Forestry website. 

Andrus, R. A., Peach, L. R., Cinquini, A. R., Mills, B., Yusi, J. T., Buhl, C., Fischer, M., Goodrich, B. A., Hulbert, J. M., Holz, A., Meddens, A. J. H., Moffett, K. B., Ramirez, A., & Adams, H. D. (2024). Canary in the forest?—Tree mortality and canopy dieback of western redcedar linked to drier and warmer summers. Journal of Biogeography, 51(1), 103–119.

Apsley, D., & Carrol, C. (2013). Growing American Ginseng in Ohio:  Selecting a Site. OSU Extension Fact Sheet F-58.  The Ohio State University. .

Bardhan, S., & Kronenberg, R. (n.d.). Forest Farming Site Selection and Preparation Guidelines Lincoln University Cooperative Research • Agroforestry Guide Sheet.

Bekris, Y., Prevéy, J. S., Brodie, L. C., & Harrington, C. A. (2021). Effects of variable-density thinning on non-native understory plants in coniferous forests of the Pacific Northwest. Forest Ecology and Management, 502.

Betzen, J. J., Ramsey, A., Omdal, D., Ettl, G. J., & Tobin, P. C. (2021). Bigleaf maple, Acer macrophyllum Pursh, decline in western Washington, USA. Forest Ecology and Management, 501.

Burkhart, E. P. (2024, April). Forest Farming: The Importance of Site Evaluation and Selection of Forest Botanicals. Gather to Grow Forest Farming Conference.

Frankson, R., K.E. Kunkel, S.M. Champion, D.R. Easterling, L.E. Stevens, K. Bumbaco, N. Bond, J. Casola, & W. Sweet. (2022). Washington State Climate Summary 2022.

Handler, S., Pike, C., & St. Clair, B. (2018). Assisted Migration. USDA Forest Service Climate Change Resource Center.

Kimmins, J.P.. (2003). Old-growth forest: An ancient and stable sylvan equilibrium, or a relatively transitory ecosystem condition that offers people a visual and emotional feast? Answer – It depends. Conference. 79.

Linders, Mary & Vander Haegen, Matthew & Azerrad, Jeffrey & Dobson, Robin & Labbe, Ted. (2010). Management Recommendations for Washington’s Priority Habitats and Species: Western Gray Squirrel.

Miles, C. A., & Daniels, C. H. (2019). GROWING WASABI IN THE PACIFIC NORTHWEST. Pacific Northwest Extension Publishing, PNW605.

Piccolo, J. J., & Wipfli, M. S. (2002). Does red alder (Alnus rubra) in upland riparian forests elevate macroinvertebrate and detritus export from headwater streams to downstream habitats in southeastern Alaska? Canadian Journal of Fisheries and Aquatic Sciences, 59(3), 503–513.

Poddar, S. (2021). MIYAWAKI TECHNIQUE OF AFFORESTATION. Krishi Science.

Rural Action. (2019). The Forest farmers handbook : a beginners guide to growing and marketing at-risk forest herbs. Rural Action.

Turk, T. D., Schmidt, M. G., & Roberts, N. J. (2008). The influence of bigleaf maple on forest floor and mineral soil properties in a coniferous forest in coastal British Columbia. Forest Ecology and Management, 255(5–6), 1874–1882.

University of Missouri. (2018). Training manual for Applied Agroforestry Practices. The Center for Agroforestry, 105(3).

USDA. (2016). Bigleaf Maple: Acer Macrophyllum.

USDA. (2025). Alley Cropping. National Agroforestry Center.