Growth performance of selected taxa as candidate species for productive tree plantations in Borneo

ABSTRACT

The establishment of commercial tree plantations in Malaysian Borneo began with a progression of various species, including Pinus caribea, Acacia mangium, Gmelina arborea, Falcataria moluccana (formerly Albizia falcataria) and Eucalyptus deglupta. Ultimately, A. mangium, intended for the production of pulplogs, dominated the plantation landscape. However, recent widespread devastation of A. mangium by the Ceratocystis pathogen in Sabah has led to a shift in plantation species, which has also necessitated a review of downstream end products. This paper analyses growth data and estimates productivity for species in a taxa trial as well as a F. moluccana progeny trial in a single trial area in Sabah. A eucalyptus hybrid (Eucalyptus urophylla x Eucalyptus grandis (UG)), Eucalyptus pellita, F. moluccana, Acacia crassicarpa and A. mangium exhibited high productivity after three years, with an average mean annual increment of approximately 35 m³ ha^?1 y^?1 or better. Mean annual increment curves show that productivity declined slightly for the eucalypts and F. moluccana after three years. Acacia species experienced a sharper decline associated with disease-caused mortality, with A. mangium the most seriously affected. The mean basic density of the UG hybrid and F. moluccana was 560 kg m^?3 and 252 kg m^?3 at six and five years of age, respectively, and E. pellita had a mean basic density of 629 kg m^?3 at six years of age. The importance of growth and wood properties in the selection of species suitable for planted forest development in the wet tropics is discussed.