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Rendimiento sostenido en bosques tropicales húmedos en América Latina: algunos desarrollos recientes

by Budowski, G; Seminario Internacional Manejo Racional de Florestas Tropicais Rio de Janeiro (Brasil) 20-21 Jun 1988.
Publisher: [sl] 1988Description: 9 p.Subject(s): RENDIMIENTO | SOSTENIBILIDAD | REGENERACION NATURAL | SISTEMAS SILVICULTURALES | BOSQUE TROPICAL HUMEDO | COSTA RICA | PERU | SURINAME | BOLIVIA | COLOMBIA | YIELDS | SUSTAINABILITY | NATURAL REGENERATION | SILVICULTURAL SYSTEMS | TROPICAL RAIN FORESTS | COSTA RICA | PERU | SURINAME | BOLIVIA | COLOMBIA | RENDEMENT | DURABILITE | REGENERATION NATURELLE | REGIME SYLVICOLE | FORET TROPICALE HUMIDE | COSTA RICA | PEROU | SURINAME | BOLIVIE | COLOMBIESummary: There is presently a very wide gap between ongoing high-grading or "mining" of commercial timber species and the management of the forest on a sustainable yield for timber and other products and services. In fact, successful cases are rather scarce although they exist. As a general rule of thumb it can be stated that the more primary ("virgin state"), the more heterogeneous the floristic composition, the higher the precipitation and the poorer the soils, the more difficult it is to reach sustained management for timber production. The corolary of this rule implies that certain secondary forests, forests where few tree species dominate (such as under swampy conditions), are more easily amenable to sustainable yield. In Costa Rica, a secondary forest stocked with valuable species was the result of careful liberation cuttings by a small farmer who selected seedlings and saplings that became established after the pasture was abandoned 20 years ago; during that period the valuable species were tended to reach the canopy. The forest today is an ecological as well as commercial success. Clearcutting and harvesting of all commercial trees in widely spaced alleys 20-50 meters wide, is practiced in Palcazú in Amazonian Peru with careful successive tending of the regeneration derived from adjacent parent trees; the system appears promising but needs long-time monitoring and initial investments to enhance the value of the harvested trees. In Surinam selective cutting for harvesting timber is practiced in a mixed moist forest with cutting cycles every 20 years, extracting 20 cubic meters of valuable species. In between these harvesting cycles, undesirable species are cut or poisoned, therefore increasing the proportion of desirable species with good form. In the Beni, in Amazonian Bolivia, management efforts are being undertaking to get the valuable mahogany forests under sustained management. Opening of the stand and vine cuttings are carefully programmed even before the harvesting cycle so as to induce the maximum of regeneration, with subsequent numerous liberation cuttings to allow valuable species to reach the canopy. It is noteworthy that the various timber companies operating in the are actively cooperating, realizing that it is in their own interest to reach sustainability. Finally the swamp forests in northwest Colombia, dominated by cativo (Prioria copaifera) and periodically inundated, are being managed in some areas for sustainable yield. Natural regeneration is very abundant but careful logging practices and subsequent liberation cuttings are necessary to achieve permanent production. The biggest threat to sustainable yield at present is conflict for land use, lack of incentives and lack of knowledge on floristic composition, particularly the careful identification of seedlings, as well as the successional dynamics of the various forest stands. Despite of these success stories, it should be clear that sustained management can only be achieved under certain favourable conditions. This is not the case for the majority of tropical American moist forests whose intrinsic value for watershed protection, genetic resources, usefulness to local indigenous groups and the potentialities to be managed for national parks, sciences and education, are far higher on a long term basis that any sustainable logging operation, with our presente state of knowledge.
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There is presently a very wide gap between ongoing high-grading or "mining" of commercial timber species and the management of the forest on a sustainable yield for timber and other products and services. In fact, successful cases are rather scarce although they exist. As a general rule of thumb it can be stated that the more primary ("virgin state"), the more heterogeneous the floristic composition, the higher the precipitation and the poorer the soils, the more difficult it is to reach sustained management for timber production. The corolary of this rule implies that certain secondary forests, forests where few tree species dominate (such as under swampy conditions), are more easily amenable to sustainable yield. In Costa Rica, a secondary forest stocked with valuable species was the result of careful liberation cuttings by a small farmer who selected seedlings and saplings that became established after the pasture was abandoned 20 years ago; during that period the valuable species were tended to reach the canopy. The forest today is an ecological as well as commercial success. Clearcutting and harvesting of all commercial trees in widely spaced alleys 20-50 meters wide, is practiced in Palcazú in Amazonian Peru with careful successive tending of the regeneration derived from adjacent parent trees; the system appears promising but needs long-time monitoring and initial investments to enhance the value of the harvested trees. In Surinam selective cutting for harvesting timber is practiced in a mixed moist forest with cutting cycles every 20 years, extracting 20 cubic meters of valuable species. In between these harvesting cycles, undesirable species are cut or poisoned, therefore increasing the proportion of desirable species with good form. In the Beni, in Amazonian Bolivia, management efforts are being undertaking to get the valuable mahogany forests under sustained management. Opening of the stand and vine cuttings are carefully programmed even before the harvesting cycle so as to induce the maximum of regeneration, with subsequent numerous liberation cuttings to allow valuable species to reach the canopy. It is noteworthy that the various timber companies operating in the are actively cooperating, realizing that it is in their own interest to reach sustainability. Finally the swamp forests in northwest Colombia, dominated by cativo (Prioria copaifera) and periodically inundated, are being managed in some areas for sustainable yield. Natural regeneration is very abundant but careful logging practices and subsequent liberation cuttings are necessary to achieve permanent production. The biggest threat to sustainable yield at present is conflict for land use, lack of incentives and lack of knowledge on floristic composition, particularly the careful identification of seedlings, as well as the successional dynamics of the various forest stands. Despite of these success stories, it should be clear that sustained management can only be achieved under certain favourable conditions. This is not the case for the majority of tropical American moist forests whose intrinsic value for watershed protection, genetic resources, usefulness to local indigenous groups and the potentialities to be managed for national parks, sciences and education, are far higher on a long term basis that any sustainable logging operation, with our presente state of knowledge.

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