Amburana cearensis has a wide geographical distribution throughout the seasonal forests and transition zones forest/savanna (Cerrado) and forest/dry seasonal forests (Caatinga) in the North, Northeast and Central Brazil. It is under threat due to over exploitation of its valuable timber and the massive convertion of the forests into agricultural land. Little is known on the growth and biomass allocation of the seasonal forests species. The hypothesis is that those species show some degree of phenotipic plasticity due to the strong seasonal light gradient found under natural conditions, in addition to those variations usually found under the canopy. This study can contribute to a better understanding of the functioning of the seasonal forest ecosystems and also to the silviculture of this species. The objective of this work was to study the growth and biomass allocation of seedlings of A. cearensis under full sun and three shading levels, in nursery conditions. The shading levels averaged 0%, 50%, 70% and 90% of the full sunlight. The experimental design was randomized with 25 replicates per treatment. Height, stem base diameter, number of leaves and leaflets were monitored from four months till 16 months of age, and dry matter was analyzed at 19 months of age. Biomass accumulation was affected by the shading levels. The total biomass was higher under full sunlight (10,55g), followed by 50%, and 70% shading, while the lowest average was found under 90% (4,59g). Eighty percent of total biomass was found in the roots for the unshaded plants. This pattern of biomass partioning predominantly to roots occurred in all treatments. The initial development under nursery conditions indicates that this species could be introduced during the early stages of a program to reclaim degraded seasonal forests, as well as used in plantation trials.
initial growth; light conditions; biomass allocation; dry seasonal forests; reforestation
