Ectomycorrhizal populations and growth of Shorea parvifolia (Dipterocarpaceae) seedlings regenerating under three different forest canopies following logging

Nine months after logging, seedlings of S. parvifolia were sampled from beneath open, closed and partially closed canopies, which resulted from the different logging treatments. Logging was done manually with minimal soil disturbance, compaction or damage to the vegetation. Assessments were made of seedling growth and ectomycorrhizal populations present on the roots. Seedlings growing under the closed canopy were smaller and possessed lower levels of mycorrhizal infection than those under open or partially closed canopies, Twenty-six ectomycorrhizal types were distinguished, with diversity greatest on seedlings growing under open and partially closed canopies. Although most mycorrhizal types occurred in less than half of the samples, occurrence of individual types was related to canopy type. Based on their frequency (number of seedlings having a mycorrhizal type) and abundance (% infection of a mycorrhizal type if present), mycorrhizal types were categorized into two main groups; those which occurred predominantly under the dosed canopy and those which occurred under both open and partially closed canopies. Many of the fungi which dominated under the open and partially closed canopies are thought of as pioneer fungi and their occurrence is discussed in relation to their methods of dispersal and sensitivity to disturbance. Implications for forest management are considered, (C) 1998 Elsevier Science B.V.