Resumo

MANCILLA VILLA, Oscar Raúl; OROPEZA MOTA, José Luis  e  MARTINEZ MENES, Mario. Evaluación de terrazas de banco para plantaciones forestales comerciales. Rev. Cien. For. Mex [online]. 2009, vol.34, n.105, pp.97-116. ISSN 1405-3586.

As an option to face the severe erosion problem that prevails in México, a project of bench terraces for commercial forest plantations was carried out in Valle de Bravo, Estado de México. The technical efficiency of the project was assessed as well as its financial feasibility. Field work was done from January to August, 2007. Vertical and horizontal ranges between the benches were based upon the following criteria: rainfall, dominant slopes (15 and 30 per cent), soil texture and the foresters' needs. Seventy 3 mx0.45 mx .90 m terraces were built in 4 ha, where 3,757 commercial trees were planted. In order to know their technical efficiency, infiltration, superficial draining and the sediments in plots with and without 0.15 m2 terraces were measured, under simulation rainfall of 140 mmh-1 intensity. Soil erosion was estimated through the Universal Soil Loss Equation. Terraces showed an efficiency of 99.09 per cent for erosion control, 43.6 per cent for infiltration increment, 74 per cent of runoff reduction and 46.6 per cent of sediment loss. In regard to financial feasibility, it was found a cost-benefit relation of 2.37, with a net present value of $ 7 800 318.77, and an internal rate of return of 129%. It was concluded that the implementation of bench terraces for commercial forest is a technically efficient financially feasible possibility.

Palavras-chave : Technical efficiency; erosion; runoff; financial feasibility; sediment; terraces.