Rainfall Partitioning in Forest Ecosystems

Rainfall partitioning in forest ecosystems refers to the processes by which gross precipitation is divided into interception by the canopy, throughfall to the forest floor and stemflow along trunks and branches. This partitioning governs the water balance, influences soil moisture dynamics, and controls the delivery of nutrients and pollutants to the soil. Canopy interception reduces the amount of water reaching the ground and contributes to evaporation losses, while throughfall and stemflow determine spatial heterogeneity in soil water inputs and chemical fluxes. The balance between these pathways is shaped by rainfall characteristics (intensity, duration and temporal gaps), canopy structure (leaf angle, branch architecture and leaf area index) and species-specific traits such as bark texture and leaf phenology. Globally, interception ratios tend to converge under similar precipitation regimes, but regional variations arise from differences in vegetation density and climate. Understanding these processes is essential for predicting forest resilience under changing rainfall patterns, for managing water resources and for modelling catchment hydrology, biogeochemical cycling and ecosystem services.

Research from Nature Portfolio

Recent studies have investigated long-term ecohydrological responses in semi-arid shrublands, demonstrating that gross rainfall amount, maximum short-term intensity, event duration and intra-event dry intervals exert a stronger control on interception efficiency than do crown characteristics. Comparative analysis of two dominant shrub species revealed species-specific thresholds for stemflow generation, distinct funnelling ratios and differing reliance on crown morphology versus rainfall variables. These insights underscore the need for decade-long monitoring to capture ecohydrological variability under shifting climatic conditions and to refine predictions of water redistribution at the soil–plant interface.

Research from all publishers

Satellite-based and model-driven assessments have produced the first high-resolution maps of global canopy interception loss, revealing that dense tropical forests account for the greatest absolute water losses while semi-arid woodlands often exhibit high interception ratios relative to gross rainfall. In Mediterranean pine forests, field measurements have shown that throughfall enriches ionic deposition compared with open-field precipitation, with elevated concentrations of key nutrients such as nitrogen and potassium and with inorganic nitrogen loads frequently exceeding critical thresholds for ecosystem health. Complementary investigations in mixed evergreen–deciduous broadleaved stands have highlighted strong seasonal fluctuations in stemflow and throughfall chemistry, driven by variations in bark morphology and leaf shedding, thereby influencing nutrient cycling and soil fertility across phenological stages.

Rainfall Partitioning in Forest Ecosystems publication trend

The graph below shows the total number of articles in rainfall partitioning in forest ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Canopy interception: The proportion of gross precipitation captured and held by leaves, branches and stems, which subsequently evaporates back to the atmosphere.

Throughfall: The portion of precipitation that drips off leaves or passes through gaps in the canopy to reach the forest floor.

Stemflow: Water that is channelled along branches and trunks to the base of vegetation, delivering concentrated inputs to near-stem soils.

Leaf area index (LAI): The one-sided leaf surface area per unit ground area, a key descriptor of canopy density.

Funnelling ratio: The efficiency metric comparing water delivered to the stem base against the amount that would fall to the ground in the absence of vegetation.

References

1. Gross rainfall amount and maximum rainfall intensity in 60-minute influence on interception loss of shrubs: a 10-year observation in the Tengger Desert. Scientific Reports (2016).
2. Comparisons of stemflow and its bio-/abiotic influential factors between two xerophytic shrub species. Hydrology and Earth System Sciences (2017).
3. Global canopy rainfall interception loss derived from satellite earth observations. Ecohydrology (2020).
4. Atmospheric deposition patterns in bulk open field precipitation and throughfall in Aleppo pine forest and black pine forest on the eastern Adriatic coast. Environmental Research (2024).
5. Hydrochemical Fluxes in Bulk Precipitation, Throughfall, and Stemflow in a Mixed Evergreen and Deciduous Broadleaved Forest. Forests (2019).