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A PRELIMINARY QUANTIFICATION OF THE IMPACTS OF ASPEN TO CONIFER SUCCESSION ON WATER YIELD ‐ I. HEAT PULSE METHODOLOGY FOR MODEL CALIBRATION 1
Author(s) -
Humphries William,
Gifford Gerald F.
Publication year - 1984
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1984.tb04668.x
Subject(s) - environmental science , transpiration , ecological succession , hydrology (agriculture) , vegetation (pathology) , evapotranspiration , abies lasiocarpa , growing season , picea engelmannii , atmospheric sciences , agronomy , ecology , geology , botany , montane ecology , biology , photosynthesis , medicine , geotechnical engineering , pathology
Twenty‐six aspen ( Populus tremuloides Michx.), 20 subalpine fir ( Abies lasiocarps (Hook.) Nutt.), and 20 Engelmann spruce ( Pices engelmanil (Parry) Engelm.) of various sizes were cut under water and suspended in permanent reserviors at a northern Utah site. The reservoirs were asealed so that all water loss was due to consumption by the trees. Sap velocities, as computed from heat pulse velocities, were related to conducting areas of the tree trunks. Computed transpiration volumes were then correlated with actual water losses from the reservoirs. Coefficients of determination (R 2 ) of 0.87, 0.86, and 0.82 were obtained for the fir, aspen, and sprucs, respectively. Reservoir water loss for each species for each season was then used to adjust a plant activity index for computing transpiration within ASPCON, a model describing the hydrology of aspen to conifer succession. The plant activity index reflects the variation in the capability of a plant community to transpire water over the year. Assumptions and limitations of the heat pulse velocity technique are also outlined.