Tree Biomass of Planted Forests in the Tropical Dry Climatic Zone: Values in the Tropical Dry Climatic Zones of the Union of Myanmar and the Eastern Part of Sumba Island in the Republic of Indonesia

Abstract

We measured the values for biomass and mean annual biomass increment (MAI) of planted forests in two parts of the Tropical Dry climatic zone (mean annual precipitation [MAP] < 1,000 mm) and in one site adjacent to one of the two parts and outside the Tropical Dry climatic zone to provide a comparison value for wet forests in the same region. MAI values of four planted forests averaged 2.60 (±1.61 SD) Mg ha -1 y -1 at a MAP of 637 mm in the central dry zone of Myanmar. The MAI of exotic fast-growing tree species (Eucalyptus camaldulensis Dehn.) did not differ significantly from those of three native non-fast-growing tree species in the central dry zone of Myanmar. MAI values appeared to be lower on land with a high gravel content in the soil or with a higher degree of erosion. In the eastern part of Sumba Island in Indonesia, MAI of planted Tectona grandis L. forest equaled 3.76 Mg ha -1 y -1 at a MAP of 500 mm and 4.49 Mg ha -1 y -1 at a MAP of 1,500 mm. A Leucaena leucocephala de Wit stand produced a higher MAI (9.62 Mg ha -1 y -1 ) at a MAP of 500 mm. The MAI values for fast-growing tree species that we measured or collected in the Tropical Dry climatic zone were less than 20% of those recorded in the Tropical Moist and Tropical Wet climatic zones and about one-third the value for forests of non-fast-growing tree species. Accordingly, fast-growing tree species may not be capable of achieving their fast growth rates under the Tropical Dry climate. This information will be useful in developing land-use programs based on plantation forestry in dry forest areas.