Estimation of pruned biomass form dendrometric parameters on urban forests: Case study of Sophora japonica

The amount of residual biomass from pruning operations of urban trees is a potentially abundant, and an underutilized source that could contribute significantly more to regional and national bio-economies than it does at present. Better utilization of woody biomass from urban green space, leisure and industrial areas could offer bio-based fuels for heat and power generation, reduce pressure on forests and reduce the management costs on a local and regional level. The aim of the work was to quantify woody biomass proceeding from pruning operations and verify the potential of using allometric relationships developed for urban forests. Quantitative results of the residual wood biomass obtained from annual pruning operations of Sophora japonica are presented in the paper according to the type of pruning practice applied. Wood formed 59.97% of total weight of all pruned material before the drying process, wood moisture content in wet basis was 44.88% and mean quantity of dry biomass (branches without leaves) obtained per tree was 18.07 kg. Regression models were applied to predict weight of dry biomass obtained per tree. Significant relationship was observed between quantity of biomass and diameter at breast height at R2 = 0.60. The analysis indicates that an abundant amount of residual biomass originating from pruning operations of ornamental species can be used to achieve ecological and energy targets. Moreover, the presented methodology creates a tool for better prediction of income, field work and logistics management for the future.