Stand content distribution and cutting regime for inland tropical rainforest
2004
Mohd Yunus Zakaria
Understanding the nature of stand content and its distribution is essential for prescribing cutting regime option that would result in a uniform stand disturbance within a harvesting area or compartment. The current management systems (SMS and MUS) are treating stand distribution within a compartment uniformly, as it is practices through the prescription of a single cutting regime prescription for the whole compartment, irrespective of its topographical features (e.g. lowland, slope and ridge top). The current practices are likely to result in over-cutting in certain areas within a compartment because felled trees are not uniformly distributed. In addition, limiting allowable cut to trees above 45 cm dbh would inevitably result in a higher content of the small size species in the future stand. This study aims to review the cutting regime prescription. Three study sites in Peninsular Malaysia were used in this study, one each in the state of Pahang, Perak and Selangor, respectively. They were all inland production tropical rainforests, comprising of lowland to upper hill forests. Stand content and distribution within 20m x 20m plots were used to investigate differences, both within and between compartments. The study indicated that the basal area content of trees having dbh 30 cm varies between sites and within sites, and the variation is higher for trees of 45cm dbh. Similar results were obtained for diptercarps 30cm dbh and 45cm dbh. The study also revealed the need to prescribe different cutting regimes within a compartment, especially for the ridge tops to avoid over-cutting in such areas. Different cutting regimes are suggested to prescribed by three topographical categories, namely (1) ridge top and upper slope, (2) lower slope and foothill, and (3) middle slope and steep valley. The study also proposed a lower cutting limit for the small size tree species, perhaps down to 30cm dbh.
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