Sustainable timber harvesting in Venezuela: a modelling approach
*Present address and correspondence: L. Kammesheidt, Visiting scientist at Institut für Weltforstwirtschaft, Bundesforschungsanstalt für Forst- und Holzwirtschaft, Leuschnerstr. 91, 21031 Hamburg, Germany (email@example.com).
- 1 Reliable data on the growth and yield of logged-over forest, to determine sustainable cutting cycles, are widely missing for the tropics.
- 2 We used the process-based model formind2.0 to analyse the growth and yield of logged-over forest in Venezuela under different logging scenarios over a period of 240 years, and compared results with unlogged stands. The performance of the model was evaluated with a detailed stability and sensitivity analysis.
- 3 In the absence of further logging, the logged-over stand approached the stand structure of mature forest in terms of bole volume and basal area after about 50–100 years.
- 4 Thirty-year cutting cycles with conventional logging methods and net extraction volumes of 45 and 60 m3 ha−1 cycle−1 did not provide sustainable yields under either of two minimum felling diameters (35 and 50 cm) that were applied. Only the 60-year cutting cycle provided sustainable yields under conventional and reduced-impact logging, with the different minimum felling diameters and a range of net volumes extracted (30–60 m3 ha−1 cycle−1).
- 5 With the longest cutting cycle (60 years), bole volume recovered to levels similar to the mature unlogged stand, but the species composition was very different.
- 6 Scenarios with reduced-impact logging provided a significantly higher timber volume than under conventional logging. The conservation of forest resources will only be possible with long cutting cycles (at least 60 years) in combination with reduced-impact logging.