Pacific Northwest Research Station

Native grasses help stem invasives

Photo credit: Tim Harrington

Scotch broom is a large nonnative shrub that has invaded forest and prairie sites throughout western Oregon and Washington. It produces many seeds that remain viable for years, enabling Scotch broom to occupy sites for decades. Several native grasses of the Pacific Northwest, however, show promise as effective competitors for inhibiting development of Scotch broom seedlings.

In greenhouse experiments, three native perennial grass species were seeded into soils containing Scotch broom seeds. Biomass of Scotch broom seedlings decreased by 72 to 90 percent when grown under grass competition. The most competitive species, spike bentgrass, was able to colonize all growing space and deplete soil water rapidly. The least competitive species, western fescue, developed more slowly. When combined with Scotch broom control treatments and seedbed preparation, native grass seeding is a promising approach for restoring invaded areas to native grasslands.

Contact: Tim Harrington, tharrington@fs.fed.us

Stewardship on national forests

Photo credit: USDA Forest Service

The PNW Research Station is collaborating with the Deschutes National Forest to explore how an ecosystem services (or nature’s benefits) approach could be used to organize and enhance forest stewardship activities in central Oregon. Current natural resource agency accounting systems define management accomplishments in terms of output-oriented program targets, such as board feet of timber sold or acres treated to reduce fire risk. These metrics describe actions undertaken, but do not account for the nonmarket goods and services provided by public lands. This project provides examples of how management activities and performance measures could be characterized in terms of ecosystem services. It is demonstrating the possibilities of this approach in a way relevant to managers and policymakers.

Contact: Robert Deal, rdeal@fs.fed.us

Restoration leads grassland conservation

Photo credit: USDA Agricultural Research Service/Bugwood.org

Worldwide, invasive exotic plants have become one of the most pressing issues of grassland conservation and management. Herbicides are the primary method used to control invasive plants. Working in the Oregon Wenaha Wildlife Area, station scientists evaluated restoration efforts applied to grasslands dominated by the invasive plant, sulfur cinquefoil, 6 years after treatments. They found that combining herbicide use with sowing native grass seed was an effective grassland restoration strategy, when combined with temporary livestock exclusion. Five herbicides were evaluated and picloram best controlled sulfur cinquefoil during the study. Seeding with native perennial grasses resulted in a 20 percent decrease in exotic grass cover. Seeding success of grassland restoration projects may appear poor in the first years because of the slow growth of native perennial grass species in the interior West, even though recovery is well underway.

Contact: Catherine Parks, cparks01@fs.fed.us

Study improves use of small logs

Photo credit: Connie Harrington

Over the past 40 years, sawmills in the Western United States have become more efficient. They now produce more lumber while using less timber. This efficiency occurred even as the size of logs used by sawmills decreased. This finding, based on a review of forest industry surveys, meant the primary technique for estimating lumber production based on volume of harvest wood was now outdated. The Scribner Log Rule was developed in 1846 and was designed to estimate board foot volume that could be produced from a log. As the wood-processing industry has diversified to produce not only lumber but pulp, composite panels, and wood-based fuels, the industry needs to be able to accurately estimate the volume of wood fiber available for use.

Thus, scientists updated conversion rates and recovery factors that are essential for estimating production efficiency, timber supply and demand, and whole-tree volume, which is required for biomass assessments and carbon accounting.

Contact: Jean Daniels, jdaniels@fs.fed.us