Masters Theses

Date of Award

12-1979

Degree Type

Thesis

Degree Name

Master of Science

Major

Forestry

Major Professor

Edward Buckner

Committee Members

Max Springer, John Rennie, H. R. DeSelm

Abstract

Changing land use along with timber kills due to inundation and sedimentation have resulted in a rapid decline in the bottomland hardwood resource of West Tennessee. Lands which have been cleared or on which drainage patterns are changing depend primarily on soil/ site factors when determining tree suitability. The opportunity for obtaining base-line data from undisturbed forest stands is rapidly disappearing due to channelization, sedimentation, impoundment by beaver and man, and land clearing.

Species composition of the forest cover and 44 soil/site variables were sampled on 127 plots from relatively undisturbed bottomland hardwood stands on the Hatchie National Wildlife Refuge. Correlation and step-wise multiple regression were used to support field observations and to identify relationships between and among soil/site variables and the absolute basal area of 33 tree species plus a dead tree category.

The soils of the floodplains of West Tennessee are principally of the Collins-Falaya-Waverly catena and the characteristic which is used to distinguish one series from another is the depth to and degree of gray mottles .

Forest cover was characterized according to six mottling depth classes, each progressively deeper. These classes were thinner and more detailed than the boundaries used for the drainage classification.

Two broad types were derived, hydroseric and mesic, each of which contained several forest communities. The hydroseric type occupied swamps, sloughs, ox bow lake margins, and low flats which were inundated for extended periods during the year. Three distinct communities, a tupelo gum, a baldcypress, and an overcup oak community, occurred at distinguishable levels of mottling and/or gleying at the soil surface. The mesic type was located on sites which were subject to flooding but were generally free of surface water most of the growing season. The communities were less discrete than those on hydroseric sites, and there was gradual transition from one forest type to another along a hydric gradient as follows: (1) sweetgum-willow oak-overcup oak community, (2) sweetgum-cherrybark oak-swamp chestnut oak community, (3) sweetgum-swamp chestnut oak-water oak-shagbark hickory community, and (4) American beech-yellow-poplar community.

Soil/site variables significant in the regression equations of eight dominant species were: (1) topographic position, (2) microsite, (3-4) texture of the A and Ci horizons, (5) depth to mottling, (6) depth to gleying, and (7) amount of available potassium at a depth of 30 to 60 cm. These suggest that the degree and duration of flooding for the hydric sites and available moisture for the mesic sites determine species composition. An increase in the change of flooding patterns results in an increase in the number of dead trees as depth to mottling decreased. This indicates that the forest cover on the floodplains of West Tennessee will gradually increase in the hydric type and decrease in the mesic type. Drainage class was too general to be an effective tool in predicting site-type, especially for the hydric communities. However, a more detailed classification using depth to mottling proved to be a good indicator of species composition on these poorly drained areas.

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

Share

COinS