PHOTOSYNTHETIC POTENTIAL OF LAUREL OAK SEEDLINGS FOLLOWING CANOPY MANIPULATION
K.W. McLeod and M.K. Burke
Abstract-The
theory of forest gap dynamics predicts that replacement individuals are
those that can most fully use the light environment gap. Along the Coosawhatchie
River in South Carolina, 12 canopy gaps were identified in a bottomland
hardwood forest dominated by laurel oak (Quercus laurifolia Michaux).
Each gap was enlarged to a uniform size by girdling large trees and removing
smaller ones. In each gap, some plots were trenched, while some plots
were left intact. Other plots, located in adjacent closed canopy forest,
were treated identically. Photosynthetic light response curves of laurel
oak seedlings were determined after gap enlargement. Seedling photosynthetic
rates were significantly greater in gaps than under closed canopy for
all light levels ± 150 µmol/m2 per second. Maximum
photosynthetic rates were approximately 50 percent of that for seedlings
growing in full sunlight. Trenching, which eliminates root competition
and increases availability to soil resources, did not affect photosynthesis.
Based on these observations, laurel oak seedlings growing in gaps should
have greater photosynthesis than those existing under full canopy.
SREL Reprint #2732
McLeod, K. W. and M. K. Burke. 2004. Photosynthetic potential of laurel oak seedlings following canopy manipulation. p. 513-519. In Proceedings of the 12th Biennial Southern Silvicultural Research Conference, edited by K.F. Connor, February 24-28, 2003, Biloxi, Mississippi, USDA Forest Service.
