Masters Theses

Date of Award

12-1976

Degree Type

Thesis

Degree Name

Master of Science

Major

Forestry

Major Professor

Eyvind Thor

Committee Members

Robert Farmer, Vernon Reich, M. E. Springer

Abstract

The objective of the study was to evaluate natural variation in specific gravity, fiber length, total extractives, and rooting ability of mature stem cuttings of American sycamore (Platanus occidentalis L.) growing on upland sites on the western Highland Rim in Middle Tennessee. Twelve upland trees were selected which had a minimum age of 12 years at breast height; for comparison purposes, an equal number of bottomland trees were selected which were also at least 12 years old at breast height. The upland trees were all located on disturbed sites with acid to highly acid soils. The first 12 years growth was analyzed for each tree by taking two 11 mm increment cores at breast height (from opposite sides of each tree) and dividing the first 12 increment rings from the pith into six two-year wood segments. The between-site difference was significant for all six wood segments for fiber length and for most of the two-year segments for total extractives, but was generally non-significant for specific gravity. Bottomland trees had longer fibers than trees from upland sites with the between-site variation accounting for about 34 percent of the total variation. Extractives in the upland population averaged 3.7 percent of the unextracted specific gravity but only 3.1 percent in the bottomland population. Among-tree differences were significant for unextracted and extracted specific gravity and fiber length for all six two-year wood segments and for total extractives for the first three segments. This variation accounted for about 50 percent of the total variation for unextracted and extracted specific gravity, 38 percent of the total variation in fiber length, and 31 percent of the total variation in the first three segments for extractives. Fiber length and extracted specific gravity increased signifi-cantly with age of the two-year segments for both populations; whereas extractives increased significantly with age for the bottomland popula-tion only. In the upland population, age accounted for 50 percent of the variation in fiber length, 16 percent of the variation in extracted specific gravity, and only 1 percent of the variation in extractives. Extracted specific gravity was significantly correlated with radial growth for the upland population (r = 0.29) and with fiber length for both the upland (r = 0.43) and the bottomland populations (r = 0.27). On the upland site, different trees produced significantly different numbers of rooted stem cuttings. The percentage of rooted cuttings ranged from 83 to 8 percent. Trees which produced greater numbers of rooted cuttings also had a significantly higher number of main roots and significantly longer main roots per cutting. In another experi-ment using four mature sycamores, five different hormone treatments, and a control applied to girdled cuttings, a significant treatment effect was observed. Of the five treatments, only two (1 percent lAA and 0.8 percent IBA) surpassed the control in number of rooted cuttings.

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