Nitrogen fixing trees in the National Program of Forest Research – PNPF

Abstract

Economic productivity increase of the planted forests without undesirable ecological alterations is one of the objetives of the National Program of Forest Research (PNPF). Marginal low fertility soils have to be used for reforestation programs in the more developed regions of Brazil. Under these constrains utilization of nitrogen fixing trees has to be properly considered in the establishment of man-made forests which have been planted at a rate of more than 400,000 ha in the last three years. For the reasons pointed out, PNPF has been putting a great deal of emphasis on the research with nitrogen fixing trees. As a result of these efforts, Mimosa scabrella has already been indicated for reforestation in the south of Brazil, and specific inoculants for Proposis pallida, the most planted tree in semi-and regions of the country, were prepared and are already available for commercial production. Selected Rhizobium strains for Leucaena leucocephala and Mimosa caesalpiniaefolia have also been produced for enlarged trials of these species. It should also be pointed out that research is under way on Dalbergia nigra, the Brazilian rosewood, which has been found to have a high potential for plantations in the Brazilian Amazon. Based on the research being carried out, a list of potential legume species for reforestation in Brazil is given in the paper.