Throughfall, stemflow, and canopy interception loss fluxes in a semi-arid Sierra Madre Oriental matorral community

Gross precipitation, throughfall, and stemflow were measured in a representative matorral subinerme study plot within a small montane basin of the Sierra Madre Oriental throughout three wet season periods. Data analysis suggests that of the 394.8 mm of cumulative gross precipitation generated by 25 sampled events, throughfall, stemflow, and canopy interception loss fluxes were 329.0±7.7 mm (83.3±1.9%), 33.5±7.6 mm (8.5±1.9%), and 32.3±10.8 mm (8.2±2.7%), respectively. Stemflow from four woody plant stems was found to be moderately correlated (r=0.54) with the product of gross precipitation multiplied by stem basal area, while the season-long Herwitz (Earth Surf. Process. Landforms 11 (1986) 401) funneling ratios for these stems averaged 21.1. The relatively large concentrations of water delivered to the bases of these plants suggest that stemflow generation may be a means of surviving drought conditions. The importance of and possible factors influencing during-event evaporation from the saturated matorral subinerme canopy, as well as recommendations for future canopy water flux studies in this plant community, are discussed.