Potential of rubber plantations for environmental conservation in Amazon Region.

The Amazon is the largest tropical rainforest in the world. Its conservation is important to avoid world climate changes, especially rising atmospheric temperature, release of greenhouse gases and control of the water cycle. The objective of this review is to discuss the potential of planting rubber trees as a source of income and C storage and to demonstrate the advantages of their introduction in a sustainable form to reduce the concentration of CO2 in the atmosphere. In the humid tropical Amazon, in upland soil areas, rubber monoculture plantations present the lowest estimated evapotranspiration compared with a natural forest. The potential carbon sequestration in total dry weight of adult rubber plantations is estimated in 275.1 ton ha-1. In the latter case this is comparable with the average values found for primary forests (240 ton ha-1) and tropical agroforestry systems (95 ton ha-1), respectively. Another advantage is the carbon accumulation in soil cultivated with rubber trees in monoculture and polyculture plantations. The cultivation of rubber trees by small farmers will have less impact on fauna because these farmers will maintain more extensive forest plots. Furthermore, if smallholdings can have at least one perennial crop as a main source of income, communities in the Amazon will reduce the rate of deforestation in comparison with that necessary for short-cycle annual crops