FLORISTIC COMPOSITION OF PASOH FOREST RESERVE, A LOWLAND RAIN FOREST IN PENINSULAR MALAYSIA

Abstract

We tabulate and analyze the tree flora of Pasoh Forest Reserve, Malaysia, based on an enumeration of all trees ≥ 1 cm diameter at breast height (dbh) ina 50-ha plot. The diversity was very high: 820 species, 294 genera and 78 families. Mean density for trees ≥ 10 cm dbh was 530 trees per ha representing about 210 species. The most diverse families were Euphorbiaceae, Myrtaceae and Lauraceae. The most abundant families across all size classes were Euphorbiaceae, Dipterocarpaceae, and Annonaceae. Among trees larger than 30 cm dbh, the Dipterocarpaceae was the most abundant family, followed by Leguminosae and Burseraceae. The forest was without dominant species. The most abundant species, Xerospermum noronhianum (Sapindaceae), accounted for only 2.5% of the total number of trees, and 2.3% of trees over 10 cm dbh. Likewise, for trees over 30 cm dbh, the most abundant species, Shorea leprosula (Dipterocarpaceae), accounted for only 3.9% of the total. The common species of canopy and emergent trees at Pasoh are also widespread throughout Malaya and are characteristic of the primary rain forest, whereas species that indicate early succession or large gaps were rare in the plot. On floristic evidence, the forest bounded by the 50-ha plot is a homogeneous example of the Malayan south-central lowland rain forest; long term studies at the site should be of general applicability within Malaysia.