A woody chamber of secrets

Abstract

In temperate tree species, adventitious roots (roots that arise from any point other than the radicle or the root axis) are usually associated with stems or low-hanging branches coming in contact with the ground. However, the splitting of a large, hollow, recently felled red maple (Acer rubrum) in northern Wisconsin revealed a profusion of adventitious roots growing into a cavity, located well above the ground surface. In this case, the hollow area had formed many years before and contained a considerable volume of humus produced from wood decay and other biotic activities. In addition to the fine roots that had grown into it, this rich organic “soil” supported a considerable biota, including at least a half-dozen large scarab beetle larvae (species unidentified; probably some type of Phyllophaga [Coleoptera: Scarabaeidae: Melolonthinae]). These larvae were almost certainly consuming the fine maple roots and detritus that accumulated in the cavity. This cavity-based microcosm demonstrates how trees can recycle nutrients and capture moisture from a rather unusual source, while supporting a community of other organisms that both contribute to (through their activities as decomposers and detritivores) and detract from (as root consumers) the efforts of the tree.