© 1996 Heron Publishing—Victoria, Canada
Growth and photosynthetic responses of four Virginia Piedmont tree species to shade
John W. Groninger, John R. Seiler, John A. Peterson and Richard E. Kreh
Department of Forestry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA / Received July 31, 1995
Summary
To determine the effects of shade on biomass, carbon allocation patterns and photosynthetic response, seedlings of loblolly
pine (Pinus taeda L.), white pine (Pinus strobus L.), red maple (Acer rubrum L.), and yellow-poplar (Liriodendron tulipifera L.) were grown without shade or in shade treatments providing a 79 or 89% reduction of full sunlight for two growing seasons.
The shade treatments resulted in less total biomass for all species, with loblolly pine showing the greatest shade-induced
growth reduction. Yellow-poplar was the only species to show increased stem height growth in the 89% shade treatment. The
shade treatments increased specific leaf area of all species. Quantum efficiency, dark respiration and light compensation
point were generally not affected by the shade treatments. Quantum efficiency, dark respiration, maximum photosynthesis and
light compensation point did not change consistently between the first and second growing seasons. We conclude that differences
in shade tolerance among these species are not the result of changes in the photosynthetic mechanism in response to shade.
Keywords:
Acer rubrum, gas exchange, Liriodendron tulipifera, photosynthesis, Pinus strobus, Pinus taeda, shade tolerance.
