TEMPORAL VARIATION IN THE WOODY UNDERSTORY OF AN OLD-GROWTH FAGUS-ACER FOREST AND IMPLICATIONS FOR OVERSTORY RECRUITMENT

Changes in woody vegetation were examined over eight years, using a 1. 05-ha permanent plot in which the location of every shrub and tree gre ater than or equal to 1 m height was mapped. There was little change i n the overstory vegetation, as expected for an old-growth forest. Much greater change occurred in the understory, primarily related to a 40 % increase in density. Differences occurred among species in the under story, as Acer saccharum and Prunus serotina increased and Fraxinus am ericana and Fagus grandifolia decreased. Canopy gap dynamics are impli cated in differences among species in the establishment and growth of individuals in the understory and their recruitment into the overstory . It is concluded that because understory is temporally variable, over story recruitment from the understory may take different courses at di fferent times in the same forest.