Tree Fruit Overview

Overview of Tree Fruit Production in The Pacific Northwest United States of America and Southern British Columbia, Canada

Timothy J. Smith

Abstract

The majority of apple, pear and sweet cherry production in North America is in the temperate deserts of Northern California and the Pacific Northwest states of Washington and Oregon in the United States, and in the adjoining region of Southern British Columbia, Canada. Major north-south mountain ranges cast rain shadows over the central interior portions of these states, ensuring both relatively temperate, dry local weather and plentiful supply of irrigation water from snow melt fed streams and rivers. Growers have taken advantage of these natural resources by producing over 100 different agricultural commodities, with deciduous tree fruits leading in total value. The climate, experienced growers and support personnel, grower financed research, modern storage and marketing have earned the region a reputation for production of consistent yields and volumes of high quality fruit.

Introduction

Over the past 60 years, North American deciduous tree fruit production has shifted from the Northeastern quarter of the USA to the West, and is now centered in the Pacific Northwest States of Washington and Oregon, Northern California, and Southcentral British Columbia. Though this region is a considerable distance from many major markets, the natural production advantages of the region more than compensate by lowering production costs and enabling consistant high fruit quality.

Most of the fruit is transported by truck 1000 to 5000 km to major markets. Approximately 30 percent of production is exported, with primary markets in North and South America, and the Asian Countries of the “Pacific Rim.”

The Region and Major Tree Fruits Produced

Physical Geography

The area described in this overview is roughly the size of the country of France, about 900 Km from north to south and 600 Km from west to east. The orchards range between 43 and 49 degrees north of the equator. The western edge of this region adjoins the Pacific Ocean, to the east are the Rocky Mountains. Lesser mountain ranges extend from north to south throughout the area. Immediately inland from the coast is a range that crests at about 1000 meters above sea level. Approximately 100-150 km inland, running North and South, are the Cascade Mountains, which are about 2000-2800 meters in height. Most of the Pacific Northwest is covered by mountains and coniferous forest, another significant percentage is high elevation desert, and less than 10 percent of the land is high quality farmland. Between the major mountain ranges are various broad valleys, plateaus, and basins. These regions are generally covered with deep soils, often from volcanic origin, as the Cascade Range has 14 relatively recent or active volcanic peaks. Tree fruit production is scattered throughout the lower elevation inter-mountain areas, but is concentrated in the valleys and basins immediately to the east of the Cascade Mountains. Orchard elevation is quite variable, ranging from 20 – 1000 meters above sea level.

The center of the region is drained by many minor streams and large rivers connected to the Columbia River, which is almost 2000 Km long, and flows at an average rate of 2840 cubic meters per second.

Climate

The climate of the region is greatly influenced by the Pacific Ocean. Cool, wet, low pressure, weather systems move from the southern Gulf of Alaska, or from the western Pacific Ocean to cross the entire Pacific Northwest USA. These weather disturbances are often separated by only 3-5 days, except during the months of June, July, August, and September, when a general high pressure system moves up from the south, bloccking these cool, moist weather systems and bringing warm, dry summers to the entire region. These Pacific Ocean air masses temper the climate during the winter, excluding the much colder continental air masses that often, farther inland, move south from central Canada. Winter temperatures, generally 0C to 10C, provide proper conditions for dormancy development and proper chilling of the trees, but rarely cause serious tree damage. However, about every 15-20 years, severe cold is experienced during a time that trees are not sufficiently hardy, and fruit trees are injured or killed.

In the fruit production areas, Spring weather develops rapidly, concentrating the various districts blossom periods. Apples bloom at lower elevations about the middle of April, and flower progressively to highest elevations about a month later. Spring frost is a threat in low, flat orchards, but is infrequent and light on slopes. Rain in the spring, summer and fall is infrequent, and usually of in the form of showers, so wetting of trees is not sufficient to lead to important disease problems in the most important production regions.  Summer daily high temperatures average about 31C during July and early August, with peaks during a few days exceeding 38C. Hail can be a problem, but it is infrequent, and mechanical hail protection is not considered necessary.  Autumn temperatures are conducive for the development of high internal quality and red color in fruit, moderate (15-22C) during the day, and cool (7-10C) at night. Season length and total heat units tend to bring fruits to maturity during the cool fall weather. Latest apple varieties are harvested in early November, after which temperatures may fall to levels that damage the fruit.

The moisture in the northern Pacific weather systems is dropped mainly on the western side and higher elevations of the Cascade Mountains, making some of the higher peaks among the wettest places on earth. The deep snow that accumulates during most winters recharges groundwater and feeds rivers and streams that often pass through the deserts situated on their leeward eastern sides. Precipitation in these East-slope rain shadow regions is scant, averaging about 125-250 mm/year and falling mostly during the winter.

Major Resources

The abundant supply of water flowing through the region provides growers a dependable supply of irrigation water in most production regions, and an abundance of relatively inexpensive hydroelectric energy to power the irrigation pumps, storage, and packing facilities. Another major resource is the system of regional irrigation districts, most of which were developed and maintained by local growers long before governments became involved in land reclamation projects. The producers have also financed an effective marketing system, and have developed numerous associations, some of which collect fees from the growers to further their interests in marketing and research.

Production Regions

From south to north:

California: The central valley of this state is one of the most productive and diverse agricultural production areas on earth. Deciduous tree fruits are produced mainly in the northern half of this valley, and constitute a very small fraction of this regions’ agricultural output. Peaches, nectarines, plums, sweet cherry, and Bartlett (Williams) pears are the major tree fruit crops produced in this region.

Medford, Oregon: This production area is in the southeast corner of the state of Oregon, between the coast mountain range and the Cascade Mountains. Winter storage pears, especially Bosc (Keiser Alexander) and Comice, are the major crops produced.

Mid-Columbia district of Oregon: This production district includes the cool, relatively wet Hood River Valley, which produces winter storage pears, predominantly D’Anjou. The eastern side of this district, near The Dalles, is comparatively warmer and has less spring precipitation, so is a major producer of sweet cherries. Most of the cherries produced in this region are sold on the fresh market, in contrast to those grown in the Willamette Valley, South of Portland, Oregon, which are mostly processed.

The Yakima Valley of Washington: This south-central Washington valley extends from the eastern slopes of the Cascade Mountains, eastward 150 km into the central lowlands of Washington. Irrigated agricultural production is diversified in this valley, but tree fruits (and grapes) are the leading crops. This dynamic growing region is the center of tree fruit production in the Pacific Northwest, producing almost half of the apples and sweet cherries grown in Washington.

The Columbia Basin of Washington: This central region of Washington State covers a region about 200 by 100 km, within which about 200,000 ha are irrigated.  Apples are the major tree fruits produced in this region, with planting and production increasing rapidly over the past 20 years. Surveys indicate apple plantings have increased to approximately 27,000 ha during this period. Most orchards are young, modern in design, relatively large, and produce diverse varieties of apples very efficiently. This region also produces sweet cherries, but relatively few pears.

The Wenatchee District of Washington: This district includes the Columbia River and Okanogan River Valleys of North Central Washington. Most fruit produced in this relatively mountainous region is grown in the narrow river valleys, including a number of lesser river valleys extending from the Columbia or Okanogan Rivers, westward into the Cascade Mountains. This region includes diverse growing conditions induced by the varied topography and elevation range. These diverse micro-climates enable growers in the area to lead North America in production of winter storage pears, especially D’Anjou and Bosc, and to grow the later season 45% of Pacific Northwest sweet cherries. About 85% of Washington winter pear production is within the  Wenatchee district.  This region also produces about 25% of Washington’s apples.   This percentage has dropped over the past 25 years, not because production has been reduced, but because production has increased at a more rapid pace in the rest of the state.

Okanagan Valley of British Columbia, Canada: This region is the warmest, driest part of Canada, and therefore serves as a center for Canadian tree fruit and wine grape production. This valley extends from the international border, connecting to the Okanogan River valley of the USA, northward about 100km. Within this region, apples, pears, sweet cherries and peaches are major crops. As this valley has a number of highly picturesque lakes and mountains, it is a popular vacation destination, and a significant percentage of the stone fruits are sold directly to the consumer. The industry is relatively small compared to the competition directly to the south, but has continued to modernize and invest in new fruit orchards and varieties. Sweet Cherries developed in this region are rapidly gaining world-wide popularity.

Table 1 Production in 1000 metric tonnes of major deciduous tree fruits in the Pacific Northwest region of North America.

Apples

Varieties: Red Delicious is still the most produced variety, but the dominance of this cultivar is history. Red Delicious had lost favor in the market during the 1980’s and 90’s, and  declined in production from 65% of the crop to about 30% of production in the year 2009.  The recent market demand has been steady now that new storage technology maintains high fruit quality over the long marketing season.  Golden Delicious, once second in production,  is also declining in popularity, and now constitutes only 10% of production. The recent cultivar mix includes Gala (21%), Fuji (14%), and Granny Smith (12%). Production of varieties such as high coloring strains of Fuji and Gala, Honeycrisp and Cripp’s Pink are rapidly increasing, as the older orchards are replanted and young orchards develop full production levels.

Production systems: Older orchards, planted on seedling or other vigorous free-standing rootstocks at 275-525 trees/ha, are rapidly being replaced by modern planting systems. Most newer orchards are trellised, non-spur varieties on Malling 9 rootstock, planted at 1400-3600 trees/ha. Most training systems have been tested, with the best economic returns from single row, 6 – 8 wire, upright training systems, planted at about 3000 – 4000 tree/ha.  “V” systems are also gaining popularity. On good sites, full yields are attained in 3-4 years after planting, on old orchard soils, full yields may not be reached until at least 5 years after establishment.

Yields: Yields vary by variety and season. However, the past decade has brought an ever-upward trend in production, as new plantings of productive orchard systems come into bearing.  While yields can be very much higher in specific instances (reports of 80 – 100 tonnes / ha are common), normal good yields are about 65 tonnes/ha for productive varieties, such as Golden Delicious and Granny Smith, 50-60 tonnes/ha for standard varieties, such as Red Delicious, and an average of 40 tonnes/ha for less productive varieties, such as Gala and Fuji.

Pest management issues: The orchards of the Pacific Northwest have much less insect and disease pressure compared to most production regions of the world. Due to the low level of precipitation in the Spring and Summer, many common foliar and fruit fungus and bacterial diseases are not present, or are relatively simple to manage. Apple scab is a potential problem in some districts, but can be controlled with 2-3 sprays on an average season. Most apples receive no sprays for the prevention of this disease. Fungicides are generally applied for powdery mildew, which can be a problem on a number of the newer varieties. Major insects include Codling Moth, the “key” pest, San Jose Scale, leafrollers, stinkbugs, and assorted other sporadic or minor pests. Most growers maintain biological control of injurious mites, and few miticides have been applied to apples since the 1960’s. Growers generally spray about 4-6 times a season to control pests, and spend about $600/ha per season for application and materials.

Pears

Varieties: Pears divided into two classes in the region. The first class is made up of Bartlett (Williams), which is mostly processed into canned halves or diced into fruit cocktail. The acreage grown for processing has been declining for the past decade. About 50 percent of the Bartlett crop is grown in a manner that produces a larger, more attractive fruit, and is sold fresh out of cold storage during the 1-6 months after harvest. The other classification of pears is the “winter” pear, mostly D’Anjou or Bosc (Kaiser Alexander), which are sold for about 2-10 months after harvest. Other winter pear varieties produced include Comice, Red D’Anjou, and Concorde (which is rapidly declining in acreage).

Production systems: Almost all pear trees in the region are 35-100 years old, planted on Bartlett seedling rootstock, and spaced to about 275 trees/ha. They are maintained at about 4.5 meters in height. When the trees are properly pruned, fruit is large and of high quality. As varieties have remained popular for generations, and high yields of superior quality fruit are common, there has been no need to remove and replace these large trees. However, it is not economically possible to plant new pear orchards on these rootstocks and tree spacing. New plantings are now more likely to be on Old Home x Farmingdale 87 rootstock, at 800 to 1200 trees/ha. These trees are free-standing, and come into production starting in year 3 or 4 after planting, and come into full production by year 7 to 9. These plantings are ultimately thinned to a spacing of about 240 to 500 tree/ha, and remain in production indefinitely.

Yields: Most standard pear varieties yield between 40 and 50 tonnes/ha ( = bins/A). The fruit sold fresh is thinned or pruned to encourage fruit to grow to a size of 200 grams or larger, preferably in the range of 220-250 grams.

Pest management issues: Pear Psylla is, by far, the key pest. The species, Cacopsylla pyricola (Foerster), is particularly suited to the climate and pear production systems of the region, and is a constant threat to fruit quality and tree health. This pest has developed resistance to all insecticides, except those it has been subjected to most recently. Growers spray 5-8 times per season, using very expensive new classes of insecticides, and may not be certain that their efforts will control the pest. There are encouraging research and demonstration projects presently underway, demonstrating enhanced control through maintenance and enhancement of biological agents. D’Anjou pears are especially susceptible to foliar damage by mites, so an intensive pest management effort continues on this variety for this pest group.

Sweet Cherries

Varieties: For many years, due to its high quality and demand in the market, the only sweet cherry variety of any economic importance in the major production areas of the region was Bing. Bing produces large, crisp, flavorful fruit, but splits and softens in rain, so production is limited to specific climatic zones. Those varieties used to pollinate Bing, such as Van, are perceived to be lesser quality, so generally received far lower prices in the market. Rainier, a large, light colored, red blushed sweet cherry has slowly gained in production over the past 20 years. In an effort to extend the production season, and avoid time periods when production is highest, varieties that ripen earlier or later than Bing have become increasingly popular over the past decade. The most commonly planted early variety is Chelan, the most popular late harvest varieties are Lapins and Sweetheart.

Planting systems: While growers in the region are well aware of the various rootstocks available from research programs around the world, Mazzard rooted trees, planted about 275 trees/ha remains the most popular planting system for cherry. Fruit size is a major factor in economic returns to the growers, and other rootstocks continue to over-set fruit and produce inconsistent fruit size in research and demonstrations in the region.  Some growers are learning to manage these trait and are taking advantage of the beneficial aspects of semi-dwarfing rootstock. Trees are usually trained to multiple upright leaders. Mature trees are heavily pruned to maintain fruit quality.

Yields: Production begins about 4-5 years after planting, and full yields are attained in about 8-10 years. Average yields are 18 tonnes/ha, but a well-managed orchard will often yield 25 tonnes/ha of large, high quality fruit.

Pest management issues: The key pest is Cherry Fruit Fly, which does very little, if any, damage to the crop, but is a quarantine issue in important markets. A pest new to the region, spotted wing drosophila, may become an important pest.  Growers spray 3-4 times per season to assure that the cherry fruit fly does not infest their fruit. Other insects that may need control include Black Cherry Aphid, Leafrollers, and Shothole Borer. The most common disease is Powdery Mildew, which does little damage if managed moderately. Other diseases that may cause damage in some orchards include Pseudomonas Bacterial Canker and Verticillium Wilt. Bird feeding damage is widespread, and growers have tried numerous devices that are said to “scare” birds, with little success.

Weather related problems: Untimely rain is the greatest threat to sweet cherry production. Rain that wets the trees for more than 10-14 hours while temperatures are 20C can split and soften near-ripe fruit, rendering it useless. Growers blow trees as dry as possible with air-blast sprayers and hovering helicopters during wet periods, and have been generally successful reducing damage during the past several seasons. In past decades, growers expected to lose their crop one or two seasons out of five, recently, crop losses have been rare. This is unlikely to continue. Wind can damage fruit, as can heat in excess of 36C that lasts more than 2-3 days during the July flower bud setting period.

Concluding Remarks

Fruit production has expanded rapidly during the past 60 years in this region, due to the many competitive advantages the growers enjoy, and the high economic returns the industry could give to the relatively proficient producer. With the advent of international trade, and the rapid expansion of production in various emerging nations, the economic picture is rapidly changing.

Apple  production has been gradually increasing, and the mix of new varieties planted promise major changes in the availability of the more popular varieties. Pear production is increasing very slowly, as demand remains static, and exports are almost counterbalanced by imports into North America. Sweet Cherry production has increased markedly, and new plantings have only recently slowed.  This is a period of rapid change and turmoil in the tree fruit industry, but the general feeling amongst the growers is cautious optimism. They are certain that their efficiency and the quality of the fruit produced in the region will give them the competitive edge in the world market, assuring the industries’ long-term survival.