A comparison of stand structure and composition following selective-harvest at Byrne-Milliron Forest

Abstract

The effects of selective-harvest on forest composition and structure in the southern range of the coast redwood (Sequoia sempervirens (D. Don) Endl.) forest have not been well documented. This case study focused on the Byrne-Milliron Forest in Santa Cruz County, California where selective-harvest is currently the primary method of timber extraction. The purpose of this research was to determine how forest structure and composition varied in regard to harvest intensity and management goals. We sampled 100 plots in the Byrne-Milliron Forest across five harvest sites. All sites had been essentially clear-cut in the late 19th or early 20th century, and subsequently selectively harvested in the late 20th and early 21st century. Four of the five sites have been managed primarily for timber production, while the fifth site, the Late Successional Unit (LSU), has been managed for old-forest conditions as well as timber production. We predicted the LSU would contain more late seral features, and that the presence of these features would be positively correlated to years since harvest, and negatively correlated to percentage cut and number of harvest re-entries. Data analysis procedures included one-way analysis of variance (ANOVA) for comparison between sites, and Pearson product-moment coefficient for correlations between variables. As expected, the LSU exhibited the most developed old-forest features, including the lowest stand density and exotic species richness among all sites evaluated. In addition, it contained the highest percentage of coast redwood associated herbaceous species and large woody debris (LWD). Results also indicated that percentage cut was the strongest predictor for canopy cover, stand density, LWD, and the cover of coast redwood associated herbaceous species. Our findings suggest that a lower percentage cut is more effective in maintaining conditions commonly associated with late seral forests such as snags, fire hollows, complex canopy structures and LWD, and these features can be present in selectively harvested stands if carefully managed.

Parent Publication

• Coast redwood science symposium—2016: Past successes and future direction

Citation

Petersen, Amy K.; Russell, Will. 2017. A comparison of stand structure and composition following selective-harvest at Byrne-Milliron Forest. In: Standiford, Richard B.; Valachovic, Yana, tech cords. Coast redwood science symposium—2016: Past successes and future direction. Proceedings of a workshop. Gen. Tech. Rep. PSW-GTR-258. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 247-258.