Regeneration of a Clear-Cut Plot in a Lowland Dipterocarp Forest in Pasoh Forest Reserve, Peninsular Malaysia

Abstract

Regeneration after clear cutting was investigated using a data set of tree censuses in 1971 and 1996 at plot 1 in Pasoh Forest Reserve (Pasoh FR), Peninsular Malaysia. Species composition and tree size larger than 10 cm in DBH (Diameter at Breast Height) were recorded in a plot (20 m X 100 m) cleared in 1971. Above ground parts of this plot were clearly cut and weighed for biomass estimation under the International Biological Program (IBP) in 1973. In 1994, we established a 6-ha plot including the above cleared plot. All trees ≧ 5 cm in DBH were tagged, measured, and identified in 1994, 1996, and 1998. We compared the species composition and spatial distribution of trees in 1996 with those in 1971. The species composition of the regenerating trees in 1996 was largely altered from the original composition before cutting. Primary forest tree species having dormant seeds, e.g. Melicope glabra and Pternandra echinata, and pioneers, Endospermum diadenum, Macaranga conifera, and M. hosei, dominated in the cleared plot. These pioneers were rare in the surrounding intact part of the 6-ha plot. Original canopy species before cutting, e.g. Koompassia malaccensis and Dipterocarpus cornutus, were very rare in the cleared plot. Nevertheless, fast-growing Shorea species such as S. leprosula and S. parvifolia were common in the plot. After clear cutting, 59 of 82 original tree species failed to return in this cleared site. These results reveal that the species composition of a primary lowland dipterocarp forest is drastically altered after a clear cutting, even though its area was small.