Towards sustainable management of mixed dipterocarp forests of South-east Asia: moving beyond minimum diameter cutting limits

Towards sustainable management of mixed dipterocarp forests of South-east Asia: moving beyond minimum diameter cutting limits

Selective logging applied in tropical forests is based on one universal criterion: a
minimum diameter cutting limit for all commercial timber species. Minimum
diameter cutting limits in mixed dipterocarp forests of the Malesia region lead to high
felling intensities (10–20+ trees per hectare). Such extraction rates create massive
stand damage (>50% of the remaining tree population), which has a negative impact
on the regeneration and growth of many harvested dipterocarp species. As such,
the minimum diameter cutting limit approach is seldom compatible with sustainable
forest management. Where basic ecological characteristics of the commercial
species are considered in timber harvesting prescriptions, mixed dipterocarp forests
appear capable of sustained timber yields, habitat conservation, and providing other
goods and services. This paper first presents the main silvicultural systems
developed in mixed dipterocarp forests of Western Malesia and then reviews current
knowledge of dipterocarp biology to finally develop guidelines aimed at improving the
ecological sustainability of production forests of Western Malesia. These guidelines,
a pragmatic reflection of science and ‘best guess’ judgement, include: (1)
integration of reduced-impact logging practices into normal management operations;
(2) cutting of eight trees per hectare or less (with a felling cycle of 40–60 years to be
determined according to local conditions); (3) defining minimum diameter cutting
limits according to the structure, density and diameter at reproduction of target
species; (4) avoiding harvesting species with less than one adult tree per hectare
(diameter at breast height [dbh] larger and equal to 50cm over an area of 50–100 ha);
(5) minimizing the size and connectivity of gaps (<600m2 whenever possible); (6)
refraining from treatments such as understorey clearing; and (7) providing explicit
protection for key forest species and the ecological processes they perform. Further
refinement is encouraged to allow for local conditions, and for other forest types.

Authors: Sist, P.; Fimbel, R.; Sheil, D.; Nasi, R.; Chevallier, M-H.

Topic: Dipterocarpaceae,logging,silvicultural systems,biology,mixed forests,forest trees,forest ecology,diversity

Geographic: East Kalimantan,Indonesia,South East Asia

Publication Year: 2003

ISSN: 0376-8929

Source: Environmental Conservation 30(4): 364-374


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