| Analysis, and ecological implications of spatio-temporal pattern in plant establishment were examined. Only trees were considered because time of establishment could be estimated from the count of annual rings. Data sets came from post-fire boreal forest, and consisted of stem positions, and time of establishment in a grid of quadrats.;Two-factor join count statistics were used to obtain the rate of expansion of a Populus balsamifera clone into an adjacent grassland. However, in more complicated circumstances, as in a post-fire boreal forest, results from join count statistics were difficult to interpret. Using the second approach, clonal Populus ramets appeared to establish away from the initial establishers in surges, contrary to what was found at a grassland interface. Seed dispersed Pinus banksiana showed an initial, clustered surge in establishment. Although overall establishment decreased with time, the reduction was greatest near the initial establishers. Establishment of shade-tolerant Picea species showed little change in time. Intraspecific competition among the initial establishers was examined based on a hypothesis of regular pattern among large, successful trees, but results unexpectedly showed spatially clustered pattern. Further analysis of large trees showed negative association between species, indicating either a response to habitat heterogeneity or interspecific competition.;Although ecological processes cannot be inferred from ecological pattern, the results of this thesis show that patterns, namely, spatial arrangements of different ages of trees, can be used to aid perception of ecological processes that are thought to occur.;The initial approach to analysis used join count statistics, where each pair of plants was characterized by a two-factor join, describing association in space and time. For a random spatio-temporal distribution, the mean and variance for two-factor joins were derived based on earlier work for one-factor joins. Observed spatio-temporal distributions from several data sets were then examined. A second analysis approach consisted of comparing the spatial pattern of different stem ages to that of the initial conspecific establishers. The results of this analysis showed how establishment changed in time. I expected different patterns to be associated according to certain species' characteristics. Finally, I examined the degree that competition operates among initially establishing stems. |
