Residual Effects of Forestry Herbicides on Floristic Diversity, Stand Structute, and Composition Eleven years after Site Preparation Treatments
The global conservation of biodiversity will require efforts at multiple levels to be successful. Because herbicides are applied annually to 100,000's of hectares of forest lands in the Southeastern Region, U.S.A, it is crucial we know their short-term and long-term impacts on forest biodivetsity, structure, and composition. It is recognized that effective applications of forestry herbicides initially decrease floristic diversity (Blake et al. 1987, Wilkins et al. 1993, Zutter and Zedaker 1988). Composition is altered because species are differentially controlled. But for how long? Structural changes are initiated because crop tree growth is usually increased. But how do alterations in structural dynamics influence diversity and composition of mid-story and under-story species? Only the companion study to the current study, which examined pine release treatments (Boyd et al.1995), has examined longer term changes in plant diversity related to earlier applications of forestry herbicides. In this current research, we tested for residual effects of site preparation applications made 11 years earlier on plant species richness, diversity, and stand structure and composition.