Exotic tree species predominate in reforestation in tropical regions worldwide. However, some native species are suitable for plantations, providing a wider variety of products. Adequate government programs of incentives, coupled with good technical advice to farmers, are needed to stimulate reforestation, especially among small and medium-sized farmers with limited financial resources. This project evaluates growth of native and exotic tree species on plantations in small and medium-sized farms in the Atlantic humid lowlands of Costa Rica, Central America. A total of 210 pure plantations, ranging in age from 6 to 11 years, were evaluated on 123 farms that had used government incentives for reforestation, and had received technical advice from local non-government organizations. For each species, seven plantations were chosen at random for study. In each plantation, plots of 15 trees each were chosen systematically for evaluation of diameter at breast height (dbh), total height, number of trees per hectare, tree form and spacing. Terminalia amazonia (J.F. Gmel) Exell, Hieronyma alchorneoides Allemao, and Vochysia guatemalensis Donn. Sm. were the most frequent species found in plantations in the region of study. Gmelina arborea Roxb. (exotic) and V. guatemalensis (native) had the highest mean annual diameter increment with 2.90 and 2.59 cm, respectively. Calophyllum brasiliense Cambess. (native) had the lowest mean annual diameter increment (1.48 cm). G. arborea and V. guatemalensis had the highest mean annual volume increment, followed by Tectona grandis (L.f) Lam. (exotic), and T. amazonia and Cordia alliodora (R&P) Cham. (both native). Although G. arborea had the greatest mean annual diameter increment, it had the lowest plantation density and problems with form. V. guatemalensis and T. amazonia, two native species, were the most promising species for reforestation, due to good growth in volume, good form, and adaptability to a variety of sites. The poor form of exotic species was related to the low intensity management methods of small farmers. Exotic species had the highest performance variability between sites, while native species showed relatively high growth homogeneity. Therefore, native species seem more promising than exotics for general use across varying ecological conditions.
Tag: choice of species
Forest plantations in Costa Rica and Nicaragua: performance of species and preferences of farmers
The area of forest plantations in the tropics worldwide is increasing as a response to the expansion of degraded lands. Rural farmers of many regions of the dry and humid areas are responding to government and other incentives, dedicating portions of their land to native and exotic tree plantations with varied uses and objectives.We evaluated the success of reforestation efforts in a dry region of Nicaragua and in a humid region of Costa Rica where reforestation has been promoted by the governments with local assistance of technical personnel and non-governmental organizations. In all farms, the survival, diameter at breast height (dbh), height, form, and health of the tree plantations were evaluated. In addition information regarding the farmer’s preferences and characteristics of the farms and the farmers was gathered through a survey including socioeconomic and silvicultural aspects. In both countries farmers used more native than exotic species for reforestation. Farmers are willing to continue reforesting as long as they continue to receive government incentives. In Costa Rica the plantations had better silvicultural management than in Nicaragua. In Nicaragua the species preferred by farmers for their growth were Azadirachta indica, Caesalpinia eriostachys, Eucalyptus spp., Gliricidia sepium, Leucaena leucocephala, and Tectona grandis. In Costa Rica the preferred species for their growth were Cordia alliodora, Gmelina arborea, Terminalia amazonia, Tectona grandis, Vochysia guatemalensis, and Virola koschnyi. The implementation of incentive programs for reforestation was a key factor in encouraging the participation of small and medium farmers.