© 2002 Heron Publishing—Victoria, Canada
Plant ecophysiology and forest response to global change
N. Buchmann (1)
1. Max-Planck-Institut für Biogeochemie, P.O. Box 10 01 64, D-07701 Jena, Germany (buchmann@bgc-jena.mpg.de) / Received December 4, 2001; accepted June 30, 2002; published online October 1, 2002
Summary
There are many ways of studying forest responses to global change. Most current national and international programs focus
on net gas exchange of the terrestrial biosphere and are typically interdisciplinary, multi-scale projects. Key objectives
of these programs are surprisingly similar to those of classical plant ecophysiology studies, i.e., to explore functional
relationships of plant or plant community responses to environmental change. Thus, common research questions that link plant
ecophysiology to ecosystem functioning can be identified for both research communities, promising complementarity and synergism
for joint research projects. Although some well-established ecophysiological relationships, such as light responses or stomatal
limitations of photosynthetic gas exchange, are currently employed in many ecosystem-scale net flux studies for gap-filling
or modeling, only 14% (n = 27) of all eddy covariance flux studies in forests (n = 196; published between 1992 and April 2002) include plant ecophysiological measurements (n = 24) or biomass and growth estimates (n = 8). Generally, emphasis is on CO2 exchange measurements at various scales (foliage, shoots, branches; n = 14) and water relations measurements (n = 11). These measurements do not fully support the typical parameterization of stand and regional models, which often need
information on canopy architecture and nitrogen nutrition. By means of a complementary research approach, valuable information
can be acquired that is unobtainable by means of a single approach. This additional information is important for the identification
of underlying biotic and environmental drivers, for the regulation of net ecosystem fluxes and their partitioning, and the
independent validation of measured net ecosystem fluxes. Thus, combining micrometeorology and ecophysiology at flux sites
is strongly recommended for ecosystem functioning studies.
Keywords:
ecosystem functioning, net ecosystem exchange.
