Height Growth Rates of Canopy Tree Species in Southern Appalachian Gaps

Annual height growth rates for saplings (1-12 m high) of 13 canopy tree species were measured in natural gaps of southern Appalachian cove forests. Study sites were limited to three federally protected tracts of land at mid (570 m) to high (1300 m) elevations in which little or no man-made disturbance was evident. Disturbances within these regions generally were due to small, single-tree gaps averaging 155 m2 for the saplings studied. In such gaps, average height growth was found to be about 30 cm/yr with species averages ranging from 18 to 49 cm/yr. The most commonly sampled species increased in growth rate in the order, Fagus grandifolia, Acer saccharum, Tilia heterophylla, Liriodendron tulipifera, and Halesia carolina. Topographic factors (i.e., slope, elevation, and aspect) and gap size and age were analyzed using a stepwise multivariate regression procedure. In general, the most rapid growth occurred for taller saplings in large young gaps in protected hillsides at lower elevations.