A method is described for implementing group selection regeneration in Appalachian hardwoods. The diverse set of definitions of the method, and the current forest demands are combined to form a flexible system of implementation that can accommodate public as well as private forests. Group selection is used where an uneven-aged silvicultural system is required and multiple objectives demanded. Several types of information are collected in a sample of the forest and then used to make the selection decision of which groups of trees to remove, and which groups to leave. / 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.

A stand-level growth and yield model was developed to predict future diameter distributions of thinned stands of mixed Appalachian hardwoods. The model allows prediction by species groups and diameter classes. Stand attributes ( basal area per acre, trees per acre, minimum stand diameter, and arithmetic mean dbh) were projected through time for the whole stand and for individual species groups. Future diameter distributions were obtained using the three-parameter Weibull probability density function and parameter recovery method. The recovery method used employed the first two non-central moments of dbh (arithmetic mean dbh and quadratic mean dbh squared) to generate Weibull parameters. Future diameter distributions were generated for the whole stand and every species group but one; the diameter distribution of the remaining species group was obtained by subtraction from whole stand values. A system of tree volume equations which allow the user t o obtain total tree volume or merchantable volume to any top height or diameter completes the model. Volumes can be calculated by species group and summed to get whole stand volume. / M.S.