Aboveground biomass modeling and tree spacing: nutritional implications for a leguminous tree species

Abstract

The search for fast-growing species associated with ecological services points out to several Brazilian species with potential for reforestation. However, information gaps regarding biomass production and sustainability need to be overcome. This study aimed to model the aboveground biomass and evaluate the influence of planting spacing on biomass and nutrient stocks, as well as the nutrient-use efficiency in stands of Anadenanthera peregrina (L.) Speg. var. peregrina. In a field experiment, 30 trees were sampled, measured, segmented into fractions such as stemwood, stembark, leaves, twigs and branches, and had their biomass evaluated. Regression models were adjusted for biomass prediction, and chemical analysis was performed to determine the macronutrients in the aboveground biomass. Spacing influenced the allocation of biomass, with the highest individual biomass production for the 5 x 5 m spacing, but with a similar overall yield per hectare among the treatments. The stands were more efficient using nutrients at wider spacings, with greater benefits when only the stemwood is harvested, possibly mitigating nutritional imbalances, such as phosphorus deficiency.

KEYWORDS: Anadenanthera peregrina, forest sustainability, silvicultural management.