Leucaena species valoration for biomass and paper production in 1 and 2 year harvest.

In order to identify faster-growing non-woody species usable for biomass and paper production, four Leucaena species (L.diversifolia, L. colinsii, L. salvadorensis and three varieties of L. leucocephala) were tested. All the Leucaena species showed a good soil and climatic adaptation to Spain Southwest except for L. salvadorensis. Studied Leucaena species showed biomass productivity ranges from 67.14 to 9.44 t ha(-1) (o.d.b.) and 43.6 to 11.4 t ha(-1) under Mediterranean conditions for the first and second year sprouts, respectively. The quantity of solubles and extractives shows similar values when compared with wood materials. Relatively lower lignin content in Leucaena (from 15.7% to 21.4%) species has been found with respect to other vegetal species. The alpha-cellulose contents (39.4-45.3%) are in the range of the normal values expected for the other non-wood raw materials. The study confirms the feasibility of organocell yield pulping process to Leucaena species. Organocell process provides an efficient delignification (kappa number 12.4 and pulp yield 42.2%) for L. leucocephala and suitably physical characteristics of paper sheet (tensile index 20.3 kNm/kg for L. diversifolia).