GreenWood Resources is the largest contiguous irrigated tree farm in the United States, stretching across 25,000 acres and boasting 7.5 million trees.

BOARDMAN Spanning six miles along Interstate 84, the GreenWood Resources  tree farm is an imposing sight for motorists passing through this small Eastern Oregon town.

As expansive as it appears, however, the stretch visible from the interstate is only a small piece of the farm.

Out of view of motorists, the 25,000-acre farm extends 13 miles south of the highway and includes 7.5 million trees.

It is the biggest contiguous irrigated tree farm in the United States.

Home to deer, owls, coyotes and other wildlife, over its 20-year life the farm has become a mini-wilderness area.

But more than a passing curiosity and a home for wildlife, the farm is a dynamic, sophisticated operation, complete with a sawmill, planer and dry kiln with a production capacity of 100 million board-feet a year.

Greenwood Resources, which purchased the tree farm in May 2007, operates the farm with an eye toward sustainability and profit.

That balance is built into everything we do, said Don Rice, Greenwoods resource manager.

The farms two irrigation systems and more than 100 pumps are operated using a computer system housed in a central office that delivers water to grids based in part on readings from soil moisture sensors.

Tacked on the wall above the computers, maps with numbered areas identify fields that are planted in uniform grids of 40 to 70 acres.

Outside, as one grid is harvested, another is planted. As one set of tree genetics gets mothballed, another emerges that produces a tree that grows a little straighter, a little faster and a little more dense. And as one market emerges, another takes a back seat.

The farm is a significant contributor to the local economy, said Lisa Mittelsdorf, economic development director for the Port of Morrow.

They have a big impact to the valuation of the county, because of new investment, new jobs; and theyre shipping lumber out of here, Mittelsdorf said.

The port recently used a $1.5 million stimulus-fund grant to rehabilitate and extend the ports south side rail spur — in large part because of the tree farm, Mittelsdorf said.

They were a big part of the reason we sought that grant, she said.

The farm also is expected to be the major supplier for a bioenergy plant that is in the planning stage at the port.

The tree farm, which is owned by a group of investors, harvests on a 12-year cycle, Rice said. During the cycle, its hybrid poplars grow to 110 feet tall. The rate of tree growth slows after 12 years.

The farm, which develops tree varieties under traditional breeding methods, has multiple genetics growing on site at any one time. The farm screens new tree varieties for growth capacity, insect and disease resistance and for growth characteristics. In windy Eastern Oregon, wind-firmness is a key trait, Rice said.

In all, the company screens for 30 different characteristics, Rice said.

The farms planting rate is 217 to 290 trees per acre.

Wood from the trees is used for a variety of purposes, including molding, upholstered furniture frames and industrial crates. Tops of trees are used for bioenergy. And smaller-diameter sections of trees are used to produce pulp chips.

The farm recently began experimenting with dedicated feedstock for the bioenergy plant planned for the Port of Morrow.

The feedstock is grown between rows on a two- to three-year rotation and treated much like a cover crop in farm crop operations.

As biomass energy comes on line, we could modify the system to capture more of the biofuels market, Rice said.

As part of its commitment to sustainability, the farm operates a 1,700-acre cooperative wildlife project with the Nature Conservancy. In addition, the farm manages a section for burrowing owl habitat. And it has installed 150 nest boxes for the saw whet owl.

Its a dual benefit, Rice said of the nest boxes. Owls prey on meadow voles, which are a pest that girdles the bark of trees and chews on drip irrigation tubes, Rice said.

Its good for the owls and its good for us, Rice said.

In all, 10 percent of the farm is dedicated to native habitat.

The farm is home to 600 deer. Deer damage seedlings, so the population is a little larger than the farm would like, but workable, Rice said.

The farm recently adapted production methods in the hopes of reducing the damage deer inflict on seedlings, by keeping trees longer in nursery settings before planting them in production fields.

The increased planting costs the method requires use of post-hole diggers — is offset by savings in reduced deer damage and lower cultivation and pruning costs. Farm managers also hope wood quality will be improved.

Portland-based Greenwood Resources  is the third owner of the tree farm in recent years. The farm previously was owned by Boise Cascade and the Potlatch Corp. Greenwood Resources  also has regional headquarters in China and Chile.

Greenwood hopes to retain ownership of the huge Oregon tree farm well into the future, Rice said.

With the current market conditions, things are very tough, Rice said. But were positioning ourselves so as the economy picks up well be ready to grow with it.