Spatio-temporal variations of throughfall and stemflow chemistry in a temperate coniferous plantatioin

Abstract:

Forest canopies create a high spatio-temporal variability of both canopy interception and atmospheric deposition, and have potential detrimental effects on the structures and functions of forest ecosystems (e.g., soil acidification, nutrient imbalances and carbon accumulation). Notwithstanding, identification of the dominant biotic and abiotic factors and processes that affect the inter- and intra-event patterns of throughfall and stemflow chemistry variability remains ambiguous. Here, we monitored hydrochemical characteristics of bulk precipitation, throughfall and stemflow in a temperate coniferous plantation, Northern China. Sequential rainfall samplers were used for sampling discrete bulk precipitation, throughfall, and stemflow during individual rainfall events. Water volume and associated inorganic anions and cations were sampled and analyzed at inter- and intra-event scales in an experimental plot. Stand characteristics (e.g., canopy openness, distance from the nearest trunk, and tree height) and climatic factors (e.g., rainfall amount, rainfall intensity and duration, and wind speed) were also determined. In addition, a canopy budget model was used to discriminate the contributions of dry deposition and canopy exchange to nutrient/pollutant inputs and internal cycling of nutrients in forest canopies. This study can provide useful insights into the generation dynamics of throughfall and stemflow chemistry with forest canopies, and enable a better framework of throughfall and stemflow in the larger context of forest hydrology and biogeochemistry.