The relationship between solar radiation interception and soil water content in a tropical deciduous forest in Mexico

Spatial and temporal patterns of potential solar radiation interception (SRI) were estimated in a tropical deciduous forest ecosystem in the West of Mexico using a Geographic Information System modeling approach. The study area was a small catchment (16 ha) divided into three altitudinal segments: top, middle and bottom. Both amount and pattern of SRI were strongly influenced by aspect. It increased with slope inclination. Catchment relief affected SRI distribution throughout the year: the highest values were on the gently sloping top segments and south-facing bottom locations, and the lowest values were in the steep north-facing bottom locations. With the onset of the rainy season soil water content (SWC) was affected by soil characteristics, but SRI was still more important than these during the rainy season. Consequently, north-facing bottom locations had less SRI but greater SWCs for longer periods. In contrast, the top and middle locations with high SRI had smaller SWCs. Vegetation structure was also affected by SWC: the north-facing bottom locations had greater tree density and, greater tree diameter at breast height and greater leaf area than the top and middle levels.