THE EFFECTS OF LOGGING ON THE ARCHITECTURE OF BORNEAN RAIN FOREST TREES

Abstract

Tree parameters were compared between trees in a logged (logged eight years ago) and an unlogged forest in Borneo. This comparison was made for 3 to 10cm diameter at breast height (dbh) trees of four tree species, namely, Mallotus penangensis, M. wrayi, Shorea johorensis and S. parvifolia. The crown position index indicated that light levels tended to be lower in the logged forest. This probably resulted from the higher tree densities in the 10 to 30 cm dbh class. Leaf display parameters did not differ between the forests. Logged forest
trees had narrower crowns than unlogged forest trees, except for M. wrayi. Mallotus wrayi and S. parvifolia had relatively thick boles in logged forest. These responses to logging may reflect recent competition for light and space (narrow crowns), and high light levels shortly after logging (thicker boles). These architectural responses to logging did not parallel architectural responses to increased light levels. After eight years the canopy of the logged forest had already closed, and light levels above juvenile trees were low. This indicated that the effects of increased light levels quickly reduced during the first years after logging.