Distribution Characteristics of Mineral Elements in Tree Leaves of a Mixed Dipterocarp Forest in Sarawak, Malaysia.

Abstract

The distribution of mineral elements in tree leaves of a mixed dipterocarp forest was studied on a plot in the Lambir Hills National Park, Miri, Sarawak. Special reference was given to specific accumulation and exclusion of a certain element. In total 237 leaf samples of 103 different trees from 62 species of 25 families were collected and their element composition was analyzed. The elements determined were N, K, Ca, Mg, Mn, Na, Fe, AI, B, Ba, Sr, Br, Zn, Rb, Cu, Ni, Ti, Cr, Sc, Pb, Co, Li, Cs, As, V, Ce, Mo and Th. Accumulator species were defined as such tree species which showed a higher concentration than the mean concentration of an element plus twice the standard deviation, excluder species as tree species with lower concentrations than the mean minus twice the standard deviation. The Ca concentration of the leaf samples were in general low with a mean value of 0.38 %. Trees of Dipterocarpaceae showed less accumulative nor exclusive tendency. Accumulators were Gluta oba for Ba, Mallotus sp. for Mn, Allantospermum borneense for Co, Koilodepas laevigatum for Ca, Sr, Co and Trigonostemon capilli pes for K, Mg, Ni and Co. An accumulation of AI by Memecylon sp. (Melastomataceae) corresponds with Masunaga's findings (Masunaga et al., 1995). In Markert (1993) Melastomataceae are recognized as Al accumulators. Co showed a specific distribution. Excluders could not be discriminated from the definition. However several species were found below the detection limit for Br, Mo, Li and Th. The wide range of element distribution in the rain forest canopy reflects the enormous diversity of absorptive or exclusive characteristics of elements among the tree species.