Water storage on tree crowns, trunks, the understory, and litter is, in many respects, one of the simplest water balance components of vegetated ecosystems, but one that is rarely parameterized in detail. Interception processes are often analogized and parameterized as the dynamic (filling and emptying) of static reservoirs, but canopy storage reservoirs and dynamics are more complex, and hence are not fully represented in most ecohydrological models. Each reservoir is itself dynamic in its spatial extent, temporal persistence, and interconnection to other reservoirs throughout the canopy space. Total water storage in the canopy depends in part on how much surface area is affected by water flowing along, and drops among, vegetative surfaces. These flow pathways and their connectivity to other canopy reservoirs also determine drainage rate, i.e., flow to stems and drip from all surfaces as throughfall to the understory or litter. Traversing the canopy in this way could take rainwater ~10−2 to 102 h (and potentially 103 h for frozen precipitation), depending on intrinsic characteristics of canopy surfaces and extrinsic meteorological factors. The aim of this chapter is therefore to describe how precipitation storage in vegetated ecosystems is measured, the major water storage reservoirs, and intrinsic and extrinsic factors affecting these reservoirs; and discuss the extent and limitations of our current knowledge about the distribution network between reservoirs.
Klamerus-Iwan, A., Link, T. E., Keim, R. F., & Van Stan, J. T. (2020). Storage and routing of precipitation through canopies. In Precipitation Partitioning by Vegetation: A Global Synthesis (pp. 16–33). Springer International Publishing. https://doi.org/10.1007/978-3-030-29702-2_2