Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This study is a quantitative analysis of the effect of fire and wind-throw on a spruce-fir-northern hardwoods forest on Peaks Island, Casco Bay, Maine. Six years after the burn, data for the effect of fire on approximately 170 acres of this forest type, were collected and categorized. The qualitative characteristics of the herb and shrub layers were noted and the soil analyzed. A random sample of the tree density was obtained by using 10 x 10 meter quadrats. In this sampling three size classes were recognized, seedling, sapling, and 1.0-4.0 inch d.b.h. For each size class the following distributions were determined: percentage frequency, percentage density, percentage basal area, density per acre, basal area per acre; and cumulative figures for the relative density, relative basal area, and relative frequency of each species over 1 inch d.b.h. A similar study was carried out on 8.8 acres of a wind-throw area, and on 144 acres of spruce-fir-northern hardwoods forest. In the latter, additional size classes up to 24.0 inches d.b.h. were added. Determining frequencies in randomly distributed quadrats resolved in a positive direction the question of whether fire and wind-throw significantly affect the plant successional trend. Since the tree species in each of the three areas were found to be nearly identical, the Chi-square criterion was employed to decide whether the density distribution was independent of the area. Two significant factors resulted: (1) Of the twenty-one species in the spruce-fir-northern hardwoods forest, thirteen were represented among the eighteen species of the wind-throw area. The distribution of these thirteen species differed significantly in the two areas. (2) Thirteen of the species of the spruce- fir- northern hardwoods forest, were represented in the burn which contained altogether fifteen species. Again, the density distribution differed significantly for the two areas. The hypothesis that the frequency distribution was independent of the area was rejected in both tests since the value of the Chi-square calculated, for the densities in each size class, was significantly different from what could be expected by chance. This substantiated the conclusion that the three unique ecological environments accounted for the quantitative distribution of their species. [TRUNCATED] / 2999-01-01