Concentric zonation of gleyed soils under individual tree canopies in southwestern British Columbia,Canada

A study was undertaken of concentric zoning of imperfectly and poorly drained, medium-textured soils around the stems of western hemlock and western red cedar in the coastal rainforest of British Columbia. The most acid profiles occur near each stem, and those having the greatest contrast in chroma between mottles and matrix occur beneath the periphery of the canopy of each tree. These circular belts of gleyed soils appear to be associated with, respectively, a limited flow of very acid water from precipitation down the stem and a much greater flow of less acid water from the periphery of the canopy.