THE RADIAL GROWTH-RESPONSE OF AMERICAN BEECH (FAGUS-GRANDIFOLIA) TO SMALL CANOPY GAPS IN A NORTHERN HARDWOOD FOREST

American beech (Fagus grandifolia, Ehrh.) is the most shade tolerant of the canopy dominant tree species in the northern hardwood forest at Hubbard Brook, New Hampshire. Nevertheless, subcanopy beech trees responded significantly to small canopy gaps (28-103 m2) by increasing radial growth compared to shaded trees. Gap-edge canopy trees did not respond to canopy gaps. Radial growth was significantly and positively correlated with DBH for shaded subcanopy trees; this relationship was much weaker for subcanopy trees in gaps. That even the canopy dominant species with the most extreme shade tolerant strategy responds substantially to canopy gaps reinforces the view of the central role of gap formation in forest dynamics.