Diagram from the study.
When rainfall that is collected on leaves and branches eventually falls to the ground, this occurs at so called “pour points” at the confluence of smaller branches and where branches change their angle. These pour points can produce drip rates that are up to 15 times larger than the rain intensity. This is an important insight to consider in hydrological modeling and forest ecology. Credit: Kunadi et al. [2024], Figure 1
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Water Resources Research

When rainfall hits the canopy of a tree, it either wets the canopy, falls on the ground directly, or reaches the ground indirectly, i.e. by flowing along the stem and falling off leaves and branches. Common hydrological insights assume that the water falling off leaves and branches is evenly distributed.

Using innovative fieldwork and rainfall simulations, Kunadi et al. [2024] show that this indirect throughfall concentrates as drips from branches at so called “pour points”, and that this may occur at rates up to 15 times that of rainfall. This has a large impact on how we understand and model the ecohydrology of forest ecosystems, as it leads to larger soil infiltration and locally wetter soils, which in turn affect soil biogeochemistry.

Citation: Kunadi, A. S., Lardner, T., Silberstein, R. P., Leopold, M., Callow, N., Veneklaas, E., et al. (2024). Introducing pour points: Characteristics and hydrological significance of a rainfall-concentrating mechanism in a water-limited woodland ecosystem. Water Resources Research, 60, e2023WR035458. https://doi.org/10.1029/2023WR035458

—Marc F. P. Bierkens, Editor, Water Resources Research

Text © 2024. The authors. CC BY-NC-ND 3.0
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