Intraspecific Variation in Sapling Mortality and Growth Predicts Geographic Variation in Forest Composition

摘要: With a view toward understanding variation in species composition among different forest communities, I examined species-specific growth and mortality of juvenile trees (2.3-78 mm diameter at 10 cm above the ground) three contrasting sites. Two sites differing soil mineralogy elevation (schist/gneiss uplands vs. calcareous bedrock valley) were situated northwestern Connecticut, USA. To examine over more extensive geographic scale, located third site central-western Michigan, Among sites, deciduous (American beech, white ash, sugar maple) showed little intraspecific models relative radial rate as function light availability. Strikingly, substantial component Michigan could be explained by sapling originally cal- ibrated for Connecticut In contrast to species, evergreen (white pine eastern hemlock) exhibited significant differences between two Intraspecific was characterized significantly estimates low light. This result suggests that other resources can simultaneously limiting, challenges application Liebig's law min- imum tree growth. For processes than did found recent both maple ash on soils comparison schist/gneiss Connecticut. general, functions upland similar, differed from site. Community dynamics each simulated with model called SORTIE, which incorporated observed Using among-site only survivorship sufficient predict dominant adult canopy, demonstrating critical importance stages community dynamics. If performs differently particular site, its interactions will also change, potentially contributing further composition. Changes species' performance response con- ditions subsequent are compositions these communities.