Quantification of the residual biomass obtained from pruning of trees in Mediterranean olive groves

This research quantified the available residual biomass obtained from pruning olive trees. The additional biomass quantified could be used as a source of energy or as raw material for the wood industry and would provide additional income for fruit producers and also a more sustainable system. Several factors were analyzed: Variety, aim of the pruning, age of the plants, size of the plantation, crop yield and irrigation. Regression models were also calculated to predict the weight of dry biomass obtained per tree and tonnes of dry biomass obtained per hectare according to the significant factors. These equations could implement logistic planning as the Borvemar model, which defines a logistics network for supplying bio-energy systems. Olive tree varieties were classified into two groups for annual pruning: high residual biomass productivity (average yield 10.5 kg dry biomass tree−1) and low productivity (average yield 3.5 kg dry biomass tree−1). Some varieties are in transition between the two groups. There are no differences in biennial pruning, reaching an average residual biomass of 33 kg tree−1. This means that in Mediterranean areas the residual biomass from olive pruning reaches an average 1.31 t ha−1 in annual pruning and 3.02 t ha−1 in biennial pruning.