Vegetation response to stand structure and prescribed fire in an interior ponderosa pine ecosystem

Abstract

A large-scale interior ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) study was conducted at the Blacks Mountain Experimental Forest in northeastern California. The primary purpose of the study was to determine the influence of structural diversity on the dynamics of interior pine forests at the landscape scale. High structural diversity (HiD) and low structure diversity (LoD) treatments were created with mechanical thinning on 12 main plots. Each plot was then split in half with one half treated with prescribed fire. During the 5-year period after the treatments, the LoD treatments showed slightly higher periodic annual increment for basal area (BA) and significantly higher diameter increment than did the HiD treatments, although HiD carried twice as much BA as LoD did immediately after the treatments. Prescribed fire did not affect growth, but killed and/or weakened some trees. No interaction between treatments was found for any variable. Stand density was reduced from the stands before treatments but species composition did not change. Old dominant trees still grew and large snags were stable during the 5-year period. Treatment has a minor impact on shrub cover and numbers. These results suggest that ponderosa pine forest can be silviculturally treated to improve stand growth and health without sacrificing understory shrub diversity.

Citation

Zhang, Jianwei; Ritchie, Martin W.; Oliver, William W. 2008. Vegetation response to stand structure and prescribed fire in an interior ponderosa pine ecosystem. Canadian Journal of Forest Research 38:909-918.