HR: 1330h
AN: H33B-02 [Abstracts]
TI: Response of Sap-Flow Measurements on Environmental Forcings
AU: * Howe, J A
EM: jahowe@indiana.edu
AF: Indiana University, Dept. of Geography - Atm. Sc., Bloomington, IN 47405 United States
AU: Dragoni, D
EM: ddragoni@indiana.edu
AF: Indiana University, Dept. of Geography - Atm. Sc., Bloomington, IN 47405 United States
AU: Schmid, H
EM: hschmid@indiana.edu
AF: Indiana University, Dept. of Geography - Atm. Sc., Bloomington, IN 47405 United States
AB:
The exchange of water between the atmosphere and biosphere is an important determinant of climate and the productivity of
vegetation. Both evaporation and transpiration involve substantial amounts of energy exchange at the interface of the
biosphere and atmosphere. Knowing how transpiration changes throughout the seasonal and diurnal cycles can help increase the
understanding of how a forest reacts to changes in the biosphere and atmosphere. A common way to estimate transpiration is
by measuring the sap flowing through the living tissues of trees. A study was conducted at Morgan-Monroe State Forest, a
mixed deciduous forest in south central Indiana (USA), to investigate how sap flow in trees responds to changes in
meteorological and environmental conditions. The heat -dissipation technique was used to estimate sap velocities from two Big Tooth Aspen (Populus grandidentata) and two Tulip Poplars (Liriodendron tulipifera). Sap velocity patterns (normalized by a
reference potential evapo-transpiration) were directly compared with meteorological and ecological measurements, such as
vapor pressure deficits, photosynthetic active radiation (PAR), rain fall, and soil moisture content. In this study, we also
investigated the uncertainties and problems that arise in using the heat dissipation technique to extrapolate the single-tree measurements to the forest scale.
DE: 0315 Biosphere/atmosphere interactions
DE: 0394 Instruments and techniques
DE: 0400 Biogeosciences
DE: 1818 Evapotranspiration
SC: Hydrology [H]
MN: 2005 Joint Assembly