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

Nine months after logging, seedlings of S. parvifolia were sampled from ben eath open, closed and partially closed canopies, which resulted from the di fferent logging treatments. Logging was done manually with minimal soil dis turbance, compaction or damage to the vegetation. Assessments were made of seedling growth and ectomycorrhizal populations present on the roots. Seedl ings growing under the closed canopy were smaller and possessed lower level s of mycorrhizal infection than those under open or partially closed canopi es, Twenty-six ectomycorrhizal types were distinguished, with diversity gre atest on seedlings growing under open and partially closed canopies. Althou gh most mycorrhizal types occurred in less than half of the samples, occurr ence of individual types was related to canopy type. Based on their frequen cy (number of seedlings having a mycorrhizal type) and abundance (% infecti on of a mycorrhizal type if present), mycorrhizal types were categorized in to two main groups; those which occurred predominantly under the dosed cano py and those which occurred under both open and partially closed canopies. Many of the fungi which dominated under the open and partially closed canop ies are thought of as pioneer fungi and their occurrence is discussed in re lation to their methods of dispersal and sensitivity to disturbance. Implic ations for forest management are considered, (C) 1998 Elsevier Science B.V.