Modelling Benefits and Costs of Urban Forest: Application to Valdebebas Park (Madrid, Spain)

Oral Presentation Abstract: Process-based models are gaining relevance for the quantification of benefits and costs derived from urban nature-based solutions (e.g. urban forests, green roofs) as a way to inform decision makers. We developed a system dynamics approach to quantify the net environmental and economic benefits of urban nature-based solutions. Based on our system dynamics approach, we present a proof-of-concept model of urban forest to quantify their net economic benefits, which was applied to a zone of Valdebebas Park (Madrid, Spain). The proof of concept model quantifies three ecosystem services (carbon sequestration, temperature and humidity regulation, and potential wood provision) and takes into account investment costs, and two operational costs (re-planting dead trees, and waste treatment of plant residues) in a spatio-temporal explicit form. The model uses a regular grid of cells of 100x100 meters and calculates ecosystem services (benefits) and costs at a monthly temporal resolution. For the application to Valdebebas Park, we modelled the ecosystems services (benefits) and operational costs in the form of biophysical outputs for 50 years. Later, we converted the biophysical outputs into monetary units making use of benefit transfer functions and aggregating outputs into yearly time steps. As part of the model, tree death is included making use of binomial probability functions, which incorporates stochasticity into the model. As a result of the application, advantages and current limitations of the model were discussed as well as its usefulness for decision making. Key words: System Dynamics; MIMES; Nature-based Solutions; Ecosystem Services; Biophysical Valuation; Monetary Valuation