Doctoral Dissertations

Date of Award

12-1983

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major Professor

Edward R. Buckner

Committee Members

H. H. Shugart, C. E. McGee, B. L. Dearden, R. A. McLean

Abstract

Low quality hardwood stands on the Catoosa Wildlife Management Area (CWMA) of the Cumberland Plateau of East Tennessee are often clearcut and burned 3 to 4 years later to maintain suitable habitat for several wildlife species. The long-term influences of these practices on stand structure and stand dynamics are poorly understood. The primary objective of this project was to develop a computer model that would predict from certain basic information the quantity and quality of vegetation that would occur on stands created by these management practices and enable the development of appropriate management strategies.

This project was the third phase in the development of a spatial gap model , FORCAT (FORests of the CAToosa), to simulate dynamics of stands on the CWMA. Phase I (Brandt et al., 1981) dealt with initial model selection and development. FORCAT was developed through revisions to the widely used FORET model (Shugart and West, 1977). Phase II (Muncy, 1980) included field studies on the effects of clearcutting of hardwood stands on the CWMA on the composition and structure of regeneration.

In the current study. Phase III, monitoring of the development of clearcuts was continued and the effects of browsing and prescribed burning on regeneration were studied. The data from this study and from Phase II were combined and used for model calibration and estimation of parameters. Major modifications to the initial version of FORCAT included the refinement of input parameters, beginning the simulation with a mature stand rather than bare ground, refinements to the simulation of sprouting and to the calculation of growth rates, and the addition of three new subroutines, TEMPE, MOIST, and SEEDPR. TEMPE calculated the number of growing degree-days each year, MOIST introduced growth limitations due to droughty conditions, and SEEDPR limited seed availability. Modifications were also made to allow periodic clearcutting and prescribed burning.

Validation of FORCAT indicated model applicability for long-term projections of species composition, tree number, and basal area. Simulation of regeneration failed, however, as stems counts were under-estimated when seed for pioneer species was abundant. Even though futher refinements are necessary, the current version was considered acceptable for use in making forest management decisions for some sites of the CWMA. Recommendations for futher research included studies of seed availability, species- and site-specific growth rates, continued monitoring of stand dynamics in clearcuts, and futher validation by application to other CWMA sites.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS