Allometric equations for estimating biomass in naturally established Prosopis stands in Kenya

Abstract

Forty five Prosopis stems of 2.5-18.0 cm diameter at breast height (DBH) were sampled at Nadapal along the Turkwel riverine forest for development of biomass and volume prediction equations for naturally established stands. Basal diameter (D30), DBH and heights were measured, felled trees and their volumes, fresh and dry weights determined. Linear and power models were evaluated for volume and biomass prediction through regression analysis of measured tree parameters. Power models yielded better results than linear models in volume and biomass prediction, with D30 and DBH being more reliable than height. Validation of models at two sites in Marigat and Bura, revealed strong significant correlations between predicted and measured tree biomass and volumes, suggesting effectiveness of the models in biomass prediction across sites. Subsequently, model development and model validation data were pooled to develop national models. Basal diameter was found to be the best variable in the development of power models for biomass and volume prediction across the country. When logarithmically transformed, biomass and volume per tree had strong significant linear relationship with basal diameter, and are accordingly recommended for quick biomass and volume estimation in the field.