The objective of this study was to describe the biology of Sassafras albidum growing on upland hardwood sites in the Ridge and Valley Physiographic Province of Virginia ln an attempt to better understand how this common understory species becomes a dominant vegetative component following clear-felling. Biomass and leaf area regressions were developed using data collected from stems growing on xeric sites (SI₅₀ < 15.2 m) and mesic sites (SI₅₀ > 18.3 m). Due to strong heteroscedasticity in the data, logarithmic allometric equations were found to be the best fitting models. No significant differences were found between biomass equations from the two site qualities. Leaf area regressions were found to be significantly different. Excavations of the root systems of stumps and residual stems found in clear-felled upland hardwood sites indicated that sassafras has a prominent lateral root system. Roots were between 5 and 15 cm in-depth and contained several sprouts. A comparison of the regeneration origin of sassafras stems growing on two sites with differing available soil moisture suggests that root sprouting was the dominant form of regeneration on dry sites, whereas on most sites root sprouting and seedling origin stem were present in equal amount. Root sprouts were significantly larger in size than seedlings. Sex ratio determinations across four site qualities showed a male biased sex ratio. Although sassafras is reported to be delicious, hermaphroditic flowers were found on all sites. Comparison between male and female plants on each site suggest that males have a slight competitive advantage. / Master of Science

Because of the extremely wide range in product values from hardwood stands, harvest decisions must consider a multiplicity of factors, many of them economic. Among these are species, tree size, tree quality, logging costs, and market alternatives. This study demonstrates how to incorporate these, using a new microcomputer program with growth projection, YIELD-MS (Hepp, 1986), to find an economically favorable regime for a particular hardwood stand. The simulation approach presented allows for economic and silvicultural comparisons of many alternative treatments that need to be considered each time a stand is re-examined for prescription in the progress of a management plan. A decision tree was developed as a systematic way of reviewing the possibilities. In order to reduce the search time necessary to move through the decision tree, some parameters were found for describing value growth of hardwood stands. The percentage of stand basal area capable of grade change (PBAGI) and the spread of percent price differentials between log grades (PPD) were tested by a series of simulation runs on data from a variety of actual stand conditions found in the Appalachian region. The results of these simulation and sensitivity tests indicate that as PBAGI and PPD increased the various economic criteria improved in value. It is concluded that recent developments in growth and yield modeling make it possible to economically evaluate various silvicultural treatments and harvest intensities at the stand level, and indications are that management for high quality can be economically desirable. / M.S.