Western Perspective: Boise Cascades Short Rotation Operations in Washington and Oregon

Steve Pottle, Boise Cascade, Wallula, WA

Abstract

There are approximately 50,000 acres (20,000 hectares) being actively managed for Short Rotation Woody Crops in California, Oregon, Washington and British Columbia. These crops are primarily of Populus and Eucalyptus species grown for pulp and paper production.

Boise Cascade began developing its Fiber Farm in the Columbia Basin in Washington and Oregon in 1991. It currently manages 17,000 acres (7,000 hectares) in cottonwood plantations ranging from 1 to 6 years of age.

These plantations are established on large blocks of irrigated farmland. Planting stock consists of dormant cuttings grown in contract stool beds. The primary challenges to plantation establishment and development are weed and pest control and irrigation system maintenance. The farm block design coupled with integrated MIS/GIS and accounting systems allows for detailed tracking and reporting of inventories, costs, and farm conditions.

Harvesting operations will begin in the months ahead and will utilize conventional logging equipment and in-field debarking and chipping. Replanting will closely follow the harvest, making effective stump and residue disposal a necessity.

Boise Cascade’s Cottonwood Fiber Farm will supply clean pulp chips, hog fuel, and fiber for corrugated medium to company owned paper mills in Wallula, Washington and St. Helens, Oregon.

Introduction

In the past decade there has been a considerable reduction in the amount of available timber in the Western United States and Canada. This loss of timber is well recognized and is related to environmental and political issues that have reduced harvests on both public and private lands.

While there has been a reduction in the amount of raw material available for forest products manufacturing, the demand for these products has remained strong. Many manufacturing facilities in the Pacific Northwest have been forced to close because of the reduction in fiber supply (at least 240 mills have closed since 1989, primarily solid wood facilities). This fiber shortage however, has also prompted the exploration of alternative sources of raw material. One of these alternative sources has been Short Rotation Intensive Culture of Woody Crops.

There are currently at least ten companies in California, Oregon, Washington and British Columbia that are either conducting Short Rotation operations or are planning to do so. Some of these efforts began in the early 1980s, so short rotation forestry is well established in the Pacific Northwest. There are now a total of 50,000 acres (20,000 hectares) in Short Rotation plantations in this region. The primary crops are hybrid cottonwood and Eucalyptus grown for paper production although there is interest in energy and specialty products use as well.

Presentation

Boise Cascade began developing its Fiber Farm in an area known as the Columbia Basin in Southeastern Washington and Eastern Oregon in 1991. The Columbia Basin is an area along the Columbia River bordered on the West by the Cascade Mountains and on the East by the Blue Mountains. It is in the rain shadow of the Cascades and thus has an arid climate that is uncharacteristic of the Pacific Northwest.

The area receives only 8 to 12 inches (20 to 30 cm) of precipitation a year, less than half of which falls as rain during the growing season. While the natural vegetation consists of sage brush and steppe grass, the sandy, alkaline soils and 200 day per year growing seasons combine to create very good growing conditions when water is made available.

As a result of the development of elaborate irrigation systems beginning in the 1950s the Columbia Basin has become one of the premiere agricultural areas in the United States. Locally grown crops include wheat, alfalfa, a variety of vegetables, fruit, and now cottonwood trees.

Boise Cascade has approximately 17,000 acres (7,000 hectares) in cottonwood plantations. These plantations have been developed on established farms with existing irrigation systems.

Site Preparation and Planting

The steps involved in establishing a cottonwood plantation on an active farm include conversion of the irrigation system to drip irrigation, site preparation and planting. This process begins months before the trees are actually put into the ground.

Planting stock consists of dormant cuttings of hybrid clones from three different species of cottonwood. These include Populus trichocarpa, P. deltoides, and P. nigra. The trees on Boise Cascade’s farm are planted by hand because they need to be adjacent to an emitter on the drip irrigation lines. A mechanical planter cannot sense where the water is and deposit a tree in the right spot.

Fertilizer Applications

Boise Cascade’s objective in fertilization is to maintain nutrient conditions that correspond to optimum cottonwood growth. Nutrient levels are measured through soil tests and foliage samples. Foliage sampling is the preferred method once the plantations are established because it gives an indication of the amount of the various nutrients that the trees are actually able to utilize and overcomes some of the micro-site variation that is inherent with irrigation.

Over the past six growing seasons, Boise Cascade has developed a standard recipe for fertilizer that meets most of the annual needs of cottonwood trees growing in the Columbia Basin. This recipe consists of a mix of nitrogen, phosphorus and zinc and is applied to the fields through the irrigation system over the course of the growing season.

Because of the sensitivity of the irrigation system to sediment, there are filter stations set up on each irrigation block. Fertilizer tanks are connected to the irrigation system at these filter stations. The fertilizer, in liquid form, is pumped into the main-lines that lead to the farm blocks. There it is mixed with the irrigation water and dispersed to the trees.

Phosphorus and zinc are fairly stable in the soil and are applied early in the growing season. Nitrogen on the other hand tends to leach and is thus applied at slower rates over several months.

The plantations are continually monitored for such problems as nutrient deficiency. If a condition does arise, it is addressed as soon as possible. Intermittent fertilizer treatments, over and above the standard recipe, are usually applied with aerial equipment. When additional fertilizer is needed it is generally in an isolated area rather than over an entire irrigation block. Therefore it is more effective to carry out spot treatments from the air than to apply extra fertilizer through the irrigation system.

Pest Management

Weeds

Pest management including weed management is a critical consideration in the production of short rotation woody crops. When excellent conditions for growing trees are created, those same conditions benefit other plants as well.

There are three primary reasons for weed control when growing cottonwood on a short rotation in an arid climate:

1. Cottonwood trees are very intolerant to shade and sensitive to competition. Until they grow beyond the reach of the various weeds, control is necessary for optimal development. Cottonwood trees also may have an allelopathic reaction to some weeds, in particular Canadian thistle and cocklebur.
2. The irrigation lines must be regularly maintained. For the farm workers to monitor the condition of the lines and to find and correct problems excess vegetation must be controlled.
3. Grasses and other weeds provide cover for rodents and other animals that can damage the trees or the irrigation lines.

Boise Cascade’s weed control program extends from before the trees are planted until the canopy closes between the rows. This usually takes two growing seasons. Methods of weed control consist of mechanical, chemical, and a combination of the two.

Before the trees are planted a combination of mechanical and chemical control is used. Trifluralin is rotovated (rototilled) into the soil. After the trees are established, but before they have developed extensive root systems, weeds are controlled mechanically by tilling or mowing between the rows. Prior to leaf out in the second growing season, any early emerging weeds can be controlled with broadcast spray. After leaf out, a hooded sprayer is used. The hood prevents the herbicide from coming into contact with the sensitive trees.

We have tried using a wicking device to apply herbicide but have had marginal results. For this method to be successful, the weeds must be at least 12 inches (30 cm) tall. Plants that are shorter than this may not be exposed to enough herbicide.

Insects

There are several insects that pose a continual challenge to Boise Cascade’s short rotation program. There are leaf beetles, moths, caterpillars, leaf rollers, grasshoppers, and stem borers. Although we have used systemic insecticides applied through the irrigation system, our primary control has been with aerial application. Aerial application has the advantage of being fast and effective, and it can used in isolated patches rather than over an entire irrigation block.

Animal Damage

There have been continual problems with several different animals. Deer browse on the youngest trees and can cause multiple tops and reduced growth. Where they have been a particular problem, hunting is allowed to control their numbers. Because of the intensity of the farming activities however, and the poor visibility in the younger trees, the extent of this hunting is extremely limited.

Mice and voles girdle the trees at the ground line, usually in the winter with a snow cover. This problem is generally associated with a buildup of grass and weeds and is best controlled through a good weed control program. Poison baits can be used as well.

Gophers eat tender tree roots and chew on irrigation lines. Gopher populations are directly related to the crop that was growing on the field before the trees were planted. Alfalfa, for instance is one of their favorites. They are controlled with poison baits.

Coyotes chew on irrigation equipment and beaver and porcupines chew on the trees. They each need to removed from the farm when their populations become too high.

Harvesting

Boise Cascade will begin harvesting its Cottonwood plantations early in 1997 producing three products: clean paper chips, hog fuel and low grade chips for corrugated cardboard. Harvesting will take place on a year-round basis according to mill needs.

Felling and bunching will be carried out with small and efficient wheeled harvesters and forwarding will be done with grapple skidders. With the soil types in the Columbia Basin and Boise Cascade’s farming practices, soil compaction is not a concern.

Delimbing, debarking, and chipping will be carried out in the field. The trees will be forwarded directly to the chipper minimizing field storage and handling. This will require that felling and skidding operations be balanced with debarking and chipping.

Transportation of the chips will be carried out in trucks for the Wallula Mill and a combination of trucks and barges for the St. Helens Mill. St. Helens is some 200 miles from our farm but on the Columbia River. Barge transportation on the river is an economical option when long distances are involved.

The bark and limbs will feed directly from the debarker/chipper unit into a tub grinder and be prepared for hog fuel use. The boiler at the Wallula Mill is sensitive to dirt so it will be necessary to keep this material as clean as possible. No on site storage will take place.

For various reasons it will be advantageous to remove stumps and large roots from the fields after the harvest. Boise Cascade is currently experimenting with several methods of stump extraction and processing. While extraction has been fairly easy, cleaning and processing have been a challenge. Stumps can be removed with either an oversized nursery lifter or a Rockwell Roto-Lifter. Both of these machines are able to operate in excess of 2 mph (3 km/hr). The stumps will be transported to the processing area and will be split, tumbled and screened before they are chipped. A second screening is likely to follow the chipping as well. If this process is successful, the material will then be transported to the Wallula Mill and used for corrugated medium.

Organization and Planning

The organizational structure of Boise Cascade’s short rotation project lends itself quite well to operations, planning, and record keeping. The project is spread over six farms that are managed as separate operating units. Each has farming and irrigation technicians assigned to it who oversee and carryout daily activities and monitor farm conditions. These people are familiar with all aspects of the respective farms and are instumental in insuring that the trees are well cared for.

The farms were established over several planting seasons, thus there are several age classes on each. This Farm by Age Class breakdown is the level at which long-term strategic planning for irrigation system development, planting, power and water requirements, and harvesting takes place. Boise Cascade’s primary strategic planning tool is a model that operates similarly to the Forest Service’s FORPLAN model and optimizes yields against costs and projected mill needs. It provides harvest schedules as well as farm development plans.

Each age class on a farm was planted over several irrigation blocks. These blocks are from 80 to 1400 acres (30 to 550 hectares) in size and each has its own independently operating irrigation system. Because the irrigation system is designed to water all of the trees within an irrigation block at the same rate, and the trees water needs vary by age, there will never be more than one age class within a single irrigation block. Because of this characteristic, harvesting and replanting will only take place on whole (not partial) irrigation blocks in a given year. The irrigation block level therefore, is the tactical planning unit. Harvest contracting and irrigation scheduling are conducted by irrigation block.

Each irrigation block is further divided into a number of planting blocks from 25 to 125 acres (10 to 50 hectares) in size. Planting blocks are clearly defined in the field and have a road or ATV trail on all four sides. This is the primary record keeping unit. Inventory data, MIS/GIS and the accounting systems are all maintained by planting block giving Boise Cascade the ability to do in-depth analysis on such factors as growth rates, ground conditions and treatment costs.

Summary

Boise Cascade has been managing short rotation woody crops in Washington and Oregon for six growing seasons. It has a total of 17,000 acres (7,000 hectares) of cottonwood trees planted on irrigated agricultural land.

The primary challenges to growing short rotation crops include irrigation system conversion and maintenance, site preparation and planting, and weed and pest control. A very intense level of management is necessary to address these issues.

Boise Cascade will complete its first rotation early in 1997 when it begins to harvest and replant its oldest fields.

Results from these short rotation operations have been excellent. The oldest trees average more than six and a half inches dbh (diameter at breast height) and 70 feet in height.

Short Rotation Management of Woody Crops has given Boise Cascade a new stable source of fiber in a region that has an increasingly limited supply.

File posted on March 17, 1998; Date Modified: February 21, 1999