PHOTOSYNTHETIC AND BIOMASS ALLOCATION RESPONSES OF LIQUIDAMBAR STYRACIFLUA (HAMAMELIDACEAE) TO VINE COMPETITION

This 2-year held study examined stomatal conductance, photosynthesis, and biomass allocation of Liquidambar styraciflua saplings in response to below- and aboveground competition with the vines Lonicera japonic a and Parthenocissus quinquefolia. Vine competition did not affect sto matal conductance of the host trees. The leaf photosynthetic capacity and photosynthetic nitrogen-use efficiency were significantly reduced by root competition with vines, either singly or in combination with a boveground competition, early in the second growing season. However, s uch differences disappeared by the end of the second growing season. T rees competing below ground with vines also had lower allocation to le aves compared with stems. Aboveground competition with vines resulted in reduced photosynthetic capacity per unit leaf area, but not per uni t leaf weight, in trees. No correlation was found between single leaf photosynthetic capacity and tree growth. In contrast, a high positive correlation existed between allocation to leaves and diameter growth. Results from this study suggest that allocation patterns are more affe cted than leaf photosynthesis in trees competing with vines.