PARENT SESSION
Contributed Oral Session 140: Forest Photosynthesis and Water Relations
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 520 B, Level 5, Palais des congrès de Montréal
Carbon gain in the understory of eastern deciduous forest.
Fetcher, Ned 1, Iacovoni, Thomas 1, Corona, Joseph2, 1 University of Scranton, Scranton, PA2 Lehigh University, Bethlehem, PA
ABSTRACT- Although positive carbon gain is necessary for plant survival in the understory, few studies have compared carbon gain for different functional groups growing in the same habitat. We hypothesized that there would be no detectable difference between carbon gain of seedlings of woody species that remain in the understory and seedlings of canopy trees. We used dynamic measurements of photosynthesis to parameterize a model of carbon gain for red oak (Quercus rubra), chestnut oak (Quercus prinus), beech (Fagus grandifolia), witch hazel (Hamamelis virginiana), viburnum (Viburnum acerifolium), and juneberry (Amelanchier spp.). Measurements of photosynthetic photon flux density were used to drive the model to provide estimates of daily carbon gain in the understory of the Lacawac Sanctuary in Northeastern Pennsylvania. Daily carbon gain was simulated for four different days during the 2003 growing season. With the exception of two plants of witch hazel, simulated daily carbon gain fell within a narrow range. Nested analysis of variance using species as a random effect was used to test whether there was a significant difference between the canopy species, red oak and beech, and the understory species, viburnum and witch hazel. There was no significant difference between functional groups in daily carbon gain on each of the four days sampled.
Key words: Carbon gain, Photosynthesis, Shade tolerance, Red oak