Integrated municipal management of waste from tree pruning and removal

Abstract

Urban forests generate a significant amount of waste from leaf fall, pruning and removal of trees. This lignocellulosic material is typically used for composting, burned (with or without energy generation) or disposed in landfills. Despite its potential use for environmentally friendly purposes, access to the material is still limited, mainly due to the lack of knowledge about its generation and quantity, difficulties in sorting, and issues related to the transport and storage of this waste. Thus, this article characterizes an urban afforestation system, quantifies the generation of waste, and proposes an integrated municipal system for the use of this waste material. After describing the procedures and operations performed for tree pruning and removal, we report a case study of the city of Piracicaba, São Paulo State, Brazil, covering a period of 15 months. We adjusted empirical equations (Log Spurr, Spurr, and Schumacher-Hall models) to estimate the volume of waste produced, serving as a basis for the development of waste quantification methods. The city was estimated to generate an average of 180 tons of afforestation waste per month, composed mainly of leaves and thin branches (69%). Composting alone was considered an inefficient use of the material (about 31% of waste is not beneficially utilized). This material can be applied for the production of different products with high added value. Models to predict the generation of waste can contribute to the planning of municipal waste management. The Schumacher-Hall and Log Spurr models produced the best results. In general, the results indicated that adequate urban planning can help reduce waste disposal and burning by local governments. Additionally, carrying out the quantification of waste and exploring the use of new recovery measures of waste from urban afforestation can help support sustainable local development.