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Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Modeling growth dynamics of juvenile loblolly pine plantations can help to address important management decisions that have to be made in young stands. The present study addressed diameter and height prediction as well as crown development analysis as functions of independent variables such as site index, relative spacing and age for trees younger than ten years old. It was found that height prediction for trees one and two years old was a function of the products of the variables site index and age (or square root of age) and relative spacing and age (or square root of age). For trees three years old and older these were also the independent variables used to explain height prediction but in this case age (or square root of age) was another significant independent variable. In regard to diameter prediction it was observed that groundline diameter was a function of age for trees one and two years old; while this variable was also a function of site index and relative spacing for trees three, four and five years old. For trees older than five years old diameter at breast height was a function of age, site index and relative spacing. The analysis of crown development showed that for trees five years old and older variables like diameter at breast height, total height, age, site index and relative spacing were significant when crown ratio was the dependent variable. For trees younger than five years old, groundline diameter and the other same independent variables (i.e. total height, age, index and relative spacing) were again found significant when crown ratio was the dependent variable. / Ph. D.

Empirical and theoretical relationships between tree crown, stem and stand characteristics for unthinned and thinned stands of planted loblolly pine were investigated. The individual tree crown measurements of crown diameter (CD) and crown projection area (CPA), and stand level measurement of the sum of crown projection areas (SCPA) were particularly important in contributing to high levels of model fit and prediction abilities of common stem and stand characteristics. As these crown measures developed over time so did corresponding stem and stand attributes. The results were similar for trees and stands located in unthinned or thinned situations; however, a limited range of data may have accounted for these similarities. The stem attributes modeled included basal area and diameter and associated growth, while the stand attributes modeled were basal area and mean dbh and associated growth. Models were also developed for the individual tree crown characteristics of CD and growth, CPA, and height to crown diameter, and for the stand level crown attributes of SCPA and growth, mean crown projection area and mean height to crown diameter. Several common competition indices were adapted to include crown information and various structural changes. The most effective competition measures in helping to predict basal area growth were point in time crown measures of SCPA and CD for trees located in unthinned stands and SCPA and CPA for trees located in thinned stands. Lastly, the effects of planting rectangularity on stem basal area growth were investigated. Two measures of rectangularity were calculated: one dealing with the ratio of distances between adjacent competing trees and another involving the ratio of the major and minor axis distances of a subject tree's crown diameter. Depending on the age of the stand,. these measures of rectangularity were found to be significant in negatively affecting stem basal area growth of trees located in unthinned stands. / Ph. D.

The effects of cultural treatments including ectomycorrhizal inoculation, chemical weed control, and slow-release fertilization on survival, growth, ectomycorrhizal colonization, and foliar nutrient levels of container-grown white (Pinus strobus L.), loblolly (P. taeda L.), and Virginia pine (P. virginiana Mill.) seedlings were studied on a recontoured and a fiat bench strip-mine site in Southwestern Virginia. One-half of the seedlings was inoculated with Pisolithus tinctorius (Pers.) Coker and Couch (Pt). A 21 g Agriform starter tablet was placed in the soil at a depth of 10 cm within 10-15 cm of each seedling in one-half of the plots at planting. Glyphosate was applied to one-half of each plot prior to planting and again later in the growing season. First year survival was not different between sites and was not significantly affected by the cultural treatments. Abundant precipitation and high soil moisture levels throughout the initial growing season may have accounted for the excellent first year survival. The combination of chemical weed control and fertilization significantly increased the growth of all three species. Pt inoculation enhanced seedling growth to some extent but high amounts of natural ectomycorrhizal colonization masked some of the effects of Pt. Levels of foliar nitrogen closely reflected the effects of each treatment on seedling growth, indicating that it was the growth-limiting nutrient for pine seedlings on these strip-mined sites. / Master of Science

M.S.

Study objectives included determining whether prescribed burning affected ponderosa pine growth; mathematically modeling the growth response to burning; and determining whether forest management history affected growth response. I sampled 188 trees from two areas near Flagstaff, Arizona; one area (Brannigan Flat) had been logged and thinned, and the other (Chimney Spring) had not; both were burned in 1976. Within each study area, control and burned plots were of similar age, vigor, height, and competition index. Trees at Chimney Spring were older, less vigorous, and taller, and had a higher competition index than at Brannigan. For each tree, periodic basal area increment (PBAI) was calculated for the years 1974-1984. To determine which variable would best model growth, postfire PBAI (individual years, 1977-1984) was correlated with previous growth (average PBAI 1974-1976); crown ratio; competition index; thinning index; and diameter. Two models of growth response were developed; one oriented toward satisfying theoretical and research goals, and the other, toward management applications. Growth was modeled using stepwise multiple linear regression, and the dependent variable was postfire PBAI. Research Model independent variables were previous growth, years (climate), and treatment-year interaction, and 72% of total variance was explained. Fire affected growth significantly and negatively for two years, and then burned trees grew similarly to control trees. Management Model independent variables were crown ratio, competition index, crown ratio, subject tree diameter, year, and treatment, and 52% of total variance was explained. This model, too, indicated a slight negative effect of burning on growth. Management history was not a significant determinant of growth response. Both models validated well; the ratio of observed-to-predicted residual mean square was 1.04 and 0.91 (Research and Management Models, respectively). Thinning index was not significantly related to postfire growth, but a change in carbohydrate allocation from stem wood to crown and root expansion could have resulted in observed burning effects. Management implications include (1) short-term growth decline may result from burning, (2) management history did not affect growth response, and (3) burning impact is greatest in dense stands of small trees.