Pacific Northwest Research Station

Biology and Culture of Forest Plants Team

2008 Science Accomplishments

Scientists compile a new fuels data set for alternative postfire reforestation treatments

Management decisions for postfire restoration must balance the benefits of revegetation against risks associated with the development of fuels and potential for reburn. After the 2002 Timbered Rock Fire in southwestern Oregon, scientists established eight alternative vegetation restoration treatments and applied them to 40 experimental treatment units. For 4 years, they have monitored the dynamics of vegetation community development, snag abundance and condition, and fuel loading on those units. Each treatment unit provides a prospective fuels model, and these data will be used in simulation studies to evaluate the effects of treatments on potential fire behavior at stand and landscape scales.

This ongoing study will provide relative measures of potential fire risks associated with the early phases of active vegetation restoration in burnt forests typical of southwestern Oregon. Managers can use this information to better design the landscape application of vegetation restoration and fuels management treatments.

Partners: Oregon State University, USDI Bureau of Land Management

To learn more, contact Paul Anderson at pdanderson@fs.fed.us.

Understory vegetation of young Douglas-fir forests is resilient to low-intensity thinning

Scientists initiated the Uneven-Age Management Project on the H.J. Andrews Experimental Forest in the late 1990s to evaluate alternative thinning practices for converting young, second-growth Douglas-fir plantations to stands that are diverse in their structure, age, and species composition.

After 5 years of multiple thinning treatments that removed few to many trees in any given area, researchers found relatively little change in the abundance and composition of the understory plant communities. The dominant woody shrubs and fern species regrew after each thinning treatment. Scientists found that the light to moderate degree of disturbance was not sufficient to offset the vigorous growth of preexisting species, or to permit the establishment of different species.

The process of stand conversion from a uniform, even-aged structural condition to a more variable, diverse uneven-aged structure requires several repeated thinnings. If the management goal is to increase the abundance and diversity of understory vegetation in young, second-growth Douglas-fir forests in the western Cascades, more substantial thinning treatments may be needed to create larger openings in the forest canopy.

Partner: USDA Forest Service Willamette National Forest

To learn more, contact Paul Anderson at pdanderson@fs.fed.us.