Influence of shrub canopy morphology and rainfall characteristics on stemflow within a revegetated sand dune in the Tengger Desert, NW China

Stemflow of xerophytic shrubs was monitored on event basis within a revegetated sand dune. Quantity of stemflow showed a clear species-specific dependence in combination with the rainfall characteristics. Results obtained revealed that for ovate-leaved C. korshinskii with an inverted cone-shaped canopy and smooth bark, the quantity of stemflow in depth accounted for 7.2% of the individual gross rainfall, while it was 2.0% for needle-leaved A. ordosica with a cone-shaped canopy and coarse bark. There were significant positive linear relationships between stemflow and individual gross rainfall and rainfall intensity for the two shrubs. An individual gross rainfall of 1.4 and 1.8 mm was necessary for stemflow generation for C. korshinskii and A. ordosica, respectively. Multiple regression analysis showed that the abiotic and biotic variables including the individual gross rainfall, mean windspeed (WS), canopy height, branch length, and canopy volume have significant influence on stemflow for C. korshinskii, whereas for A. ordosica, the notable influencing variables were individual gross rainfall, stem diameter, and leaf area index. Generally, WS has less effect on stemflow than that of rainfall for A. ordosica. The correlation relationship between individual gross rainfall and funneling ratio showed that the funneling ratio attains its peak when the gross rainfall is 13 and 16 mm for C. korshinskii and A. ordosica, respectively, implying that the canopy morphology emerged as determining factors on funneling ratio decrease when the individual gross rainfall exceeds these values. In comparison, higher WS increased the funneling ratio remarkably for C. korshinskii than A. ordosica due partly to the greater branch length and canopy projection area in C. korshinskii. Funneling ratio can be used as an integrated variable for the effects of canopy morphology and rainfall characteristics on stemflow. The implication of stemflow on water balance and its contribution to sustain the shrubs and the revegetation efforts was discussed. Copyright (c) 2013 John Wiley & Sons, Ltd.