POPULATION-DYNAMICS OF TREE SEEDLINGS IN A MIXED DIPTEROCARP RAIN-FOREST BEFORE AND AFTER LOGGING AND CROWN LIBERATION

Southeast Asian dipterocarp rainforests have largely turned into secon dary forests due to heavy, repeated selective leggings, Secondary fore sts are expected to re-establish the original primary forest compositi on through natural succession, Post-logging silvicultural operations, especially liberation cutting of the pioneer/secondary forest trees, a re conducted in order to enhance this succession, These techniques may not achieve the desired goal. We studied the structure and developmen t of seedling stock of three stands of mixed dipterocarp forest type i n southern Borneo, including (I) a stand logged over 12 years ago and treated by crown liberation 5 years later, (II) an untreated logged-ov er stand, and (III) an unlogged, untreated stand, over a period of 2 y ears. We found no indication that succession of the seedling stock in logged-over forests would take any directed course towards the species composition of the unlogged control area within long (12 years) or sh ort (2 years) periods. Seedling density of logged-over stands was mark edly higher than that of the unlogged area. Within 12 years, pioneer s pecies were almost totally eliminated from the seedling stock of the u ntreated area, but to a lesser extent than that of the treated one, Di pterocarp seedlings were most abundant in the untreated logged-over st and. Crown liberation appeared to favour the recruitment of the seedli ngs of light-demanding pioneer species, instead of enhancing the regro wth of dipterocarp timber stock.