Simulation of evapotranspiration and drainage from mature and clear‐cut deciduous forests and young pine plantation

Abstract

Prosper, a phenomenological model of water exchange between soil, plant, and atmosphere, was used to simulate evapotranspiration and annual drainage for 2 years from a mature oak-hickory forest in the southern Appalachians. The simulation was tested by comparing drainage to measured streamflow. In a year of unusually high precipitation the simulated annual drainage was within 1.5% of measured streamflow. Simulations were also performed by using the same 2 years of meteorologic data, but vegetation parameters were changed to represent a young white pine plantation and a regrowing hardwood forest I year after clear-cutting. The model estimated that drainage for an average rainfall year was reduced 20 cm by a 16-year-old white pine plantation and increased 36 cm by clear-cutting. These results were comparable to changes of -20 and +38 cm observed in watershed experiments at Coweeta Hydrologic Laboratory. Simulated evapotranspiration during the summer was nearly identical for hardwood and pine forests, while winter and early spring water loss was greater for pine. Simulation suggests that the greater evapotranspiration by pine was due to increased interception in all seasons and increased transpiration in the dormant season. For the clear-cut area, simulated evapotranspiration was considerably less than it was for the pine or hardwood forest and thus caused simulated soil moisture contents to be greater during the summer season. of the Forest Biomass, International Union of Forest Research Organizations, College of Life Sciences and Agriculture, University of Maine, Orono, 1973. Swift, L. W., Jr., Effect of forest cover and mountain physiography on : the radiant energy balance, D.F. thesis, Duke Univ., Durham, N. C., 1972. Swift, L. W., Jr., and R. J. Luxmoore, Computational algorithm for solar radiation on mountain slopes, Memo Rep. 73-10, 20 pp., East.

Seasonal changes of leaf area index (LAI) in a tropical deciduous forest in west Mexico

“…As a result, LAI has been identified as a key parame-ter in studying and modelling ecosystem function at local, regional and global scales (Swift et al, 1975;Parton et al, 1992). LAI varies greatly among ecosystems, ranging from less than 1 m 2 m~2 in arid ecosystems, up to 20 in some conifer stands (Kozlowski et al, 1991).…”

Long term responses of streamflow following clearcutting and regrowth / Réactions à long terme du débit des cours d'eau après coupe et repeuplement

“…While this investment has yielded results that are significant, invaluable, and the most precise evaluation available for streamflow response to forest regrowth, they do not fully explain why the measured responses occurred. However, these integrated basin responses and the extensive data will provide an ideal opportunity to utilize process oriented évapotranspiration models (Swift et al, 1975) to further increase our understanding of the forest hydrological cycle.…”

Forest Influences on Climate and Water Resources at the Landscape to Regional Scale

“…Clearing riparian forests increases radiation reaching the forest floor thus elevate stream water temperature (Swift and Messer 1971;Swift 1973Swift , 1982. Conifer forests (i.e., white pine plantations) have lower albedo than deciduous hardwood forests (Swift et al 1975), thus more energy is available for evapotranspiration, partially explaining the 20 % lower water yield observed for one watershed that was converted from native southern hardwoods to pine forests. Actual forest ET at Coweeta is generally higher than potential ET (PET) as estimated with references to water or grass surfaces (Rao et al 2011).…”