Effect of site characteristics and 1st- and 2nd-year seedling densities on forest development in a northern hardwood forest

Abstract

Factors influencing the initial colonization and subsequent (18-year) survivorship of trees were studied in two clear-cut watersheds in the Hubbard Brook Experimental Forest in New Hampshire. Variation in microsite conditions associated with the harvest operations (e.g., soil scarification, slash) and physical gradients within the watershed were particularly important in determining 1st- and 2nd-year densities of pin cherry (Prunuspensylvanica L.) and yellow birch (Betulaalleghaniensis Britt.), whereas factors relating to seed availability and the presence of advance seedlings and sprouts were important in determining 1st- and 2nd-year white ash (Fraxinusamericana L.) density. The 1st- and 2nd-year densities of sugar maple (Acersaccharum Marsh.) and beech (Fagusgrandifolia Ehrh.) were relatively independent of factors measured in this study and were probably related to both seed availability and the presence of advance seedlings and sprouts. Physical site factors immediately following clear-cutting continued to be important in determining the density of pin cherry and yellow birch at stand age 18 years, whereas 2nd-year sugar maple and beech seedling and sprout densities were the most important factors in determining the densities of these species 18 years following clear-cutting.