Theses and Dissertations


Carson James

Issuing Body

Mississippi State University


Roberts, Scott D.

Committee Member

Fan, Zhaofei (Joseph)

Committee Member

Frey, Brent R.

Date of Degree


Document Type

Graduate Thesis - Open Access


With a growing desire to generate structural characteristics of late-successional conifer forests, managers are commonly seeking an approach to increase structural heterogeneity in otherwise simple second-growth stands. This study examined understory response to experimental thinning on the Olympic Peninsula of Western Washington. Variable-density thinning within the Olympic Habitat Development Study was found to have significant effects on both the density of seedling recruitment as well as early growth of western hemlock (Tsuga heterophylla (Raf.) Sarg.). In additional analysis, pre-commercial understory thinning, implemented by the Olympic National Forest, produced no observable acceleration in basal area growth. Results suggest that understory development is sensitive to previous management history as well as post-treatment stand structure. Better understanding the sources of variability in understory tree response to non-uniform thinning and understory density management will be principle in evaluating the efficacy of these treatments relative to traditional methods.