Comparative physiology of a central hardwood old-growth forest canopy and forest gap

Abstract

Concerns of poor oak regeneration, changing climate, biodiversity patterns, and carbon cycling in the Central Hardwoods have prompted ecological and physiological studies of old-growth forests and their role in maintaining the landscape. To examine the effects of old-growth canopy structure on the physiological productivity of overstory and understory species, we measured physiological parameters of canopy trees in an old-growth oak-maple forest in east-central Indiana. Mid-day measurements of photosynthesis, transpiration, stomatal conductance, photosynthetically-active radiation, humidity, vapor pressure deficit, air temperature, and ambient carbon dioxide levels were taken during the peak of the growing season along the profile of a canopy gap within the forest, and along a height transect within the continuous canopy. Productivity, physiological, and micro-environmental profiles are presented for this old-growth forest and their relationship to current and future tree species composition and forest structure is discussed.

Citation

Gillespie, A. R.; Waterman, J.; Saylors, K. 1993. Comparative physiology of a central hardwood old-growth forest canopy and forest gap. In: Gillespie, Andrew R.; Parker, George R.; Pope, Phillip E.; Rink, George: eds. Proceedings of the 9th Central Hardwood Forest Conference; Gen. Tech. Rep. NC-161. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station: 46-54