Polycyclic Methods

The Celos Silvicultural System (CSS), developed by the Wageningen Agricultural University of the Netherlands, has been proposed as a technically feasible balance of economic and ecological aspects of timber production in the seasonal evergreen forest of Surinam (De Graaf and Poels 1990). The CSS is a cost-effective way of growing more marketable wood in previously exploited neotropical rain forest, based on relatively short felling cycles of 20-30 years (De Graaf 2000). It can be used in natural or lightly used forest. The Celos system is designed for areas that are large enough to supply an economically viable timber processing unit. When the area under forest is abundant, an extensive system with low output per hectare is adequate.

The Celos system is based on the use of silvicultural operations in several cycles of interventions. For example, a harvest cycle may consist of an initial extraction of 10 m3 with subsequent interventions after 8 and 16 years, with a target of a total of 20 m3 of lumber/ha and a felling cycle of 20 years. Refinement and liberation are used as needed to stimulate the growth of desired individuals that are left as residuals.

The method is good for areas with relatively large tracts of forest thus permitting the extraction of fewer trees per hectare but resulting in a relatively high amount of total timber extracted. It should be noted that no complete set of treatments has yet been applied. The state of the forest after more than one rotation should be tested in the existing long-term plots where selective logging may be continued as intended under the CSS (Dekker and De Graaf 2003). Most management systems for natural tropical forests today are modifications of the SMS or the CSS geared to suit the local ecological characteristics of the forest as well as the economic conditions of the region (Box 5.1).

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