Pacific Southwest Research Station

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Research Paper

Title: Abies concolor growth responses to vegetation changes following shrub removal, northern Sierra Nevada, California

Author: Conard, Susan G.; Sparks, Steven R.

Date: 1993

Source: Res. Paper PSW-RP-218. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 9 p

Station ID: RP-PSW-218

Description: Conifer productivity in western North America is often severely inhibited by competing vegetation. Abies concolor [Gord. and Glendl.] Lindl. (white fir) is an important species over much of this area, yet little information is available on response of A. concolor to vegetation management treatments. We revisited two sites in the northern Sierra Nevada to assess the responses of naturally regenerated A. concolor saplings to vegetation recovery 8-9 years after release treatments. Treatments caused major and persistent shifts in vegetation structure and composition on both sites. Differences in individual tree growth within treatments were strongly correlated with structure and composition of neighboring vegetation, even where no treatment effects were observed. At Rice Canyon, height growth of trees was still 270 to 380 percent of controls after 8 years. At Sattley, positive growth responses had disappeared after 6 years. We attribute different site responses to better site quality at Rice Canyon and poorer success of treatments at controlling competitors at Sattley. Great variability in response between sites illustrates the strong effect of site characteristics on response to release treatments and the importance to managers of anticipating such differences before making treatment decisions.

Key Words: Abies concolor, white fir, conifer release, vegetation management, competition, Sierra Nevada

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Citation

Conard, Susan G.; Sparks, Steven R.  1993.  Abies concolor growth responses to vegetation changes following shrub removal, northern Sierra Nevada, California  Res. Paper PSW-RP-218. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 9 p.