CORVALLIS - Hardwood trees, once thought of as overgrown weeds in Pacific Northwest forests, are now being viewed as quite the opposite - valuable for wood products, critical to wildlife and healthy forest ecosystems, and even useful to prevent pollution.

In Oregon, multi-million dollar industries are blossoming, ecologists are coming to understand the unique capability of hardwoods to nurture certain animal species, and their role in long-term sustainable forestry is gaining new appreciation, say forestry experts at Oregon State University.

"Red alder, a leading hardwood species, now supports a lumber, veneer and pulp industry with an annual employment income of over $100 million," said David Hibbs, an OSU associate professor of forest science.

Hibbs is also the director of the Hardwood Silviculture Cooperative at OSU. Now entering its second decade, this cooperative has worked to redefine the role, use and perception of the 25 major hardwood tree species in Oregon.

At least partly because of that, Hibbs said, success stories are mounting:

-Research on how to manage red alder, which already is the dominant tree on several million acres of western Oregon forests and is often used in furniture production, has helped boost a growing industry.

-Hybrid poplar silviculture is booming, with tens of thousands of acres planted almost as an agricultural crop for both chip, solid wood and veneer products.

-Poplar plantations are also showing value as "nutrient filters" to help treat municipal waste water and prevent stream pollution.

-More is being learned about the "nitrogen-fixation" potential of alder, the ways in which it can naturally fertilize forest soils and may eventually be planted in tandem with Douglas-fir to increase its growth.

-Leaf litter from deciduous hardwoods, when mixed with conifer needles, may increase decomposition and nutrient cycling rates.

-Ecologists are coming to understand how various hardwood species provide the seeds, berries and nuts that support diverse bird populations, small mammals and - further up the food chain - such predators as spotted owls.

-A Coast Range study found a linear increase in bird diversity as the percent of hardwoods in a conifer forest increased from zero to 50 percent.

"Recent research has uncovered some fascinating links," Hibbs said. "For example, in southern Oregon the northern spotted owl eats a lot of wood rats. Wood rats eat acorns and madrone berries."

The subtle interplay of hardwood trees in wildlife enhancement, soil fertility, stream riparian zones and forest succession is just now coming to be better understood, Hibbs said. And private industry, long fixated on the value of conifers almost to the exclusion of everything else, is waking up to the potential of hardwoods.

"Also, it's not just a case of the big industries doing hardwood plantings and harvesting," Hibbs said. "With poplar plantations we're now seeing hundreds of small farmers getting their feet wet, planting maybe five to 30 acres at a time to see how the economics will work out."

More and more, Hibbs said, the dollars and cents of hardwood silviculture pencil out quite nicely - Northwest Hardwoods has been the most profitable division of Weyerhaueser. And several other major industries are heavily involved in hardwood silviculture.

Overcoming the hardwood-as-weed mentality of the past is still an obstacle, he said, but with the push for ecosystem management, the role of hardwoods in Pacific Northwest forests should only increase.

OSU researchers and forestry Extension are continuing aggressive efforts to bring updated knowledge about hardwood silviculture to the field.

"If nothing else, hardwoods are a real key to the beauty of our forests," Hibbs said. "It's the aspen, dogwood and maple that make our brilliant fall color. The white trunks of alder and aspen provide a winter accent.

"And if you want to see the best wildflowers," he added, "look under a bottomland hardwood stand in the spring."

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David Hibbs, 541-737-6077