Tree Huggers

This organic matter, composed of decaying leaves and branches, airborne particulates and moisture, is called canopy soil or arboreal soil.

"This is the first study to look at the distribution patterns of canopy soils across forests and one of very few studies that have sought to examine canopy soil properties."

Murray says tree canopies in the tropical montane forest systems are especially dense, with thick moss, soil and an abundance of epiphytes - plants that grow on other plants - often referred to as "Air plants" - that are not parasitic and have little or no attachment to other obvious nutrient sources.

"I initially conducted surveys to assess canopy soil abundance from the ground with binoculars. But it was really necessary to climb up into the trees to get an accurate picture of what was going on."

"I think canopy soil stores 0.4 to 4 percent of total soil carbon in the forests where it is found, which is not being counted in ecosystem carbon budgets."

Mentored by USU Biology Professor John Stark and former USU faculty member Bonnie Waring, the latter now with Imperial College London and an author on the paper, Murray says the team's results indicate both climate and tree size play an important role in canopy soil abundance, carbon stocks and chemistry.

"Climate, particularly fog and temperature changes, appear to drive canopy soil abundance across forests, while tree size determines canopy soil abundance within a forest," she says.