Masters Theses

Date of Award

8-1984

Degree Type

Thesis

Degree Name

Master of Science

Major

Botany

Major Professor

H. R. DeSelm

Committee Members

C. C. Amundsen, B. C. Mullin

Abstract

A study of chestnut oak forests as they occur on ridge tops in the Ridge and Valley Physiographic Province and adjacent areas was conducted from June 1979 to October 1979. The objectives of this study were: (1) to document the composition of the community over the length of the study area, (2) to analyze relationships of tree taxa to selected site, soil and topographic features, and (3) to analyze the relationship between the radial growth of selected chestnut oak trees and selected environmental parameters.

The point-centered quarter method was used to sample trees. Transects were placed along the crests of ridges that appeared, after reconnaissance, to be dominated by chestnut oak (Quercus prinus). Each transect was 200 m long and included 20 sampling points. This study encompassed 35 transects located within eight states. The tree 10 cm dbh or greater that occurred closest to the sampling point in each compass quarter was measured and recorded, Saplings, trees less than 10 cm but greater than 2.5 cm dbh, and subsaplings, tree species greater than 1 m tall but less than 2.5 cm dbh, were sampled in a plot located at each sampling point in the transect. Data on herbaceous plants were collected at each sampling point from one 1 m2 plot. Selected chestnut oak trees were cored in each transect to determine rate of radial growth of the species for the preceding 10 year period.

Soil data were collected for each transect. Thickness of the A and B horizons was measured, where possible, and stone cover was estimated in the field. Texture and pH of the A and B horizons were determined in the laboratory.

Topographic and site properties were determined by field measurement and from topographic maps.

Climatic properties were determined from the Climatic Atlas of the United States (United States Department of Commerce 1968). Properties included in this study were yearly and seasonal values for precipitation and temperature and values representing incoming sunlight and solar radiation.

The measures of importance for both the trees and saplings, relative species basal area, importance value (IV 300), relative species density and relative species frequency for the trees and the latter two for the saplings, were easily predicted using stepwise multiple regression analysis. R2 values were calculated as high as 0.65 for the trees and 0.72 for the saplings. Equations for Quercus rubra had the highest predictive value among the tree taxa. The equations predicting importance of Quercus prinus had R2 values ranging from 0.29 to 0.51 among the trees and from 0.45 to 0.56 among the saplings. The two variables that represent climatic influences, latitude and mean total solar hours, were the most important variables predicting the measures of importance. The most important predictor among soil variables was sand in the A horizon. Of the topographic variables, elevation was most important.

The stands investigated in this study were similar throughout the study area. Quercus prinus was the overwhelming dominant species in the communities. There were usually one or two additional abundant species in each transect. South of Tennessee, Quercus velutina, Q. coccinea and Pinus virginiana were the common associates. To the north, Quercus rubra and Acer rubrum commonly occurred. Two small tree species occurred throughout, Cornus florida and Sassafras albidum. The shrub cover was dominated by ericaceous species.

Analysis of the radial growth data of Quercus prinus showed differences in growth rate over the latitudinal gradient represented by the study area. The greatest growth rates occurred from Tennessee southward.

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