GAP DYNAMICS IN AN OHIO ACER-FAGUS FOREST AND SPECULATIONS ON THE GEOGRAPHY OF DISTURBANCE

Forest gaps were monitored for 12 yr in an old-growth forest dominated by Acer saccharum and Fagus grandifolia. Most gaps were formed by single tree falls, although some larger ones were created by the deaths of 2-4 canopy trees. Gap closure rates suggest that most saplings need the occurrence of >1 gap to reach the canopy. Newer, small-scale disturbances, because of their geometry, occur near older disturbances at high rates. After gaps form, woody vegetation increases in density for 5-10 yr, then decreases in density. The four main species of this study show different patterns of response, with optima as follows: small gaps of all ages for Acer, old gaps of all sizes for Fagus, large young gaps for Fraxinus americana, and large gaps of all ages for Liriodendron tulipifera. The presence, size distribution and species composition of saplings immediately preceding gap formation help determine which species will dominate the gap. -from Author