HR: 1330h
AN: B52A-1023    [PDF]
TI: Rainfall Partitioning Within Juniper Canopies: Hydrologic Implications for Semiarid Communities
AU: * Owens, M K
EM: m-owens@tamu.edu
AF: Texas Agricultural Experiment Station, 1619 Garner Field Road, Uvalde, TX 78801 United States
AU: Lyons, R K
EM: rk-lyons@tamu.edu
AF: Texas Cooperative Extension, 1619 Garner Field Road, Uvalde, TX 78801 United States
AU: Alejandro, C L
EM: c-alejandro@tamu.edu
AF: Texas Agricultural Experiment Station, 1619 Garner Field Road, Uvalde, TX 78801 United States
AB: Juniper canopies are ideally structured to intercept rainfall and redirect it to the base of the tree, thus altering the hydrology of the site. The amount of water redirected, and the amount lost to interception and evaporation, may be a significant portion of the annual rainfall. We monitored interception and rainfall partitioning in juniper canopies at 10 sites covering a 24 to 36 inch rainfall gradient over a 3 year period. Averaged over all 10 sites, about 47% of the precipitation falling on juniper trees is intercepted by the canopy of the tree and evaporated back to the atmosphere, 5% is intercepted by the litter and duff beneath the tree, and 48% actually reaches the ground surface for either recharge or plant growth. The amount of rainfall intercepted by the canopy is most affected by the intensity and duration of the storm. At high intensities, such as .5 inch over a 3 hr period, only 20% is intercepted by the canopy and litter. The remainder is available for either plant growth or aquifer recharge. When rainfall is less intense, such as 3 inches over a 19 hour period, all of the rainfall less than .5 inch is intercepted by the tree and litter. Not until nearly 1 inch of rain has fallen does an appreciable amount of water actually reach the ground surface beneath the tree. Most of the rainfall events observed over the last several years have been small events of less than .5 inches. These events, although common, do not contribute to soil water under juniper trees and are largely ineffective.
DE: 1818 Evapotranspiration
DE: 1836 Hydrologic budget (1655)
DE: 1851 Plant ecology
DE: 1854 Precipitation (3354)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting