Differences in Rainfall Interception Losses for Three Tree Species Common to Colorado: Populus tremuloides, Picea engelmannii, and Pinus ponderosa

Abstract

Rainfall interception is the amount of rainfall retained in a canopy after a storm event has occurred. This term is also referred to as rainfall interception loss since the water retained in the canopy is evaporated or "loss" back to the atmosphere and does not touch the forest floor. Although dependent on the total amount of rainfall, interception loss is also greatly affected by the type of species, tree structure, and specific characteristics such as lea area. This study serves to answer the following research questions: are there differences in rainfall interception losses between Populus tremuloides (aspen), Picea engelmannii (Engelmann spruce), and Pinus ponderosa (ponderosa pine), and if so, what canopy characteristics influenced the interception? The results showed that the conifers, Engelmann spruce and ponderosa pine, contained higher interception losses compared to aspen in a majority of the samples. Many of the samples showed that a larger stand density and basal area corresponded with smaller interception losses. This could be due to a variety of reasons including perimeter drip, inclined rainfall, and wind. If urban planners were to choose the tree species that could decrease runoff, then ponderosa pine would be the best choice out of the three species.