Effects of leaf hydrophobicity and water droplet retention on canopy storage capacity

Canopy storage capacity is influenced by several variables, including canopy surface area, canopy architecture, and wind. Different species with the same canopy area, but with differences in leaf hydrophobicity and water droplet retention, may produce different values of canopy storage capacity. The objective of this study was to investigate if leaf hydrophobicity and water droplet retention are additional influences on canopy storage capacity. Specifically, this study tested the hypothesis that species with the highest leaf hydrophobicity and the lowest water droplet retention had the lowest canopy storage capacity on a per leaf area basis. Seven tree species from Colorado, United States were selected for experimentation. Five branches from each species were lopped, positioned under a rainfall simulator, and connected to a balance to record the mass gain of the branches by rainfall interception during 17min of rainfall simulation. Each branch was destructively sampled following rainfall simulation to calculate the leaf and woody surface areas. The rank order of leaf surface storages at canopy storage capacity for each species corresponded to the rank order of leaf hydrophobicity and water droplet retention for each species. Species with the highest leaf surface storage had the lowest leaf hydrophobicity and the lowest water droplet retention. The significance of leaf hydrophobicity and water droplet retention as variables that influence canopy storage capacity is a largely unexplored topic in ecohydrology. Copyright (c) 2012 John Wiley & Sons, Ltd.