Quantifying the effect of non-spatial and spatial forest stand structure on rainfall partitioning in mountain forests, Southern China

Abstract

Forest stand structure plays an important role in rainfall interception and is a focal point in forest hydrology. Previous studies mainly looked at the effect of non-spatial attributes of stands while a few studies addressed the influence of spatial features. The aim of this study was to quantify the effect of stand structure on rainfall partitioning using diameter, height, leaf area index (LAI), neighbourhood comparison, mingling index and uniform angle index. The results revealed that the average accumulative throughfall, stemflow and interception loss accounted for 72.8%-83.2%, 0.5%-11.3% and 13.3%-26.2% of total precipitation, respectively, and significant differences existed in rainfall partitioning. The accumulative interception loss was negatively related to uniform angle index (a measure of tree spatial distribution patterns) as stand structure attribute was not available at each rainfall event. The effects of stand structure on throughfall, stemflow and interception loss varies considerably under different rainfall conditions. The LAI was significantly associated with interception loss for heavy rainfalls. The mingling index was negatively related to stemflow; however, significant relationships existed between mingling index, throughfall, and interception loss for light rainfall (drizzle). Significant positive relationships existed between uniform angle index and stemflow, while significant relationships existed for interception loss for light and heavy rainfalls. The results highlight that stand structure in combination with rainfall patterns influence rainfall partitioning.