The Future of the Urban Forest

Abstract

With nearly 70% of people living in cities by 2050 (United Nations, 2018), our urban environments are being put to the test, with more severe and frequent heat waves, droughts, floods, ongoing biodiversity loss, air pollution, and land subsidence. To sustain and increase the liveability and climate resilience of cities, the design and implementation of urban green infrastructure, with the urban forest as its backbone, is one of the most critical solutions (Spronken-Smith & Oke, 1998; Rosenzweig et al., 2015; Norton et al., 2015). However, the current indifference that runs through the veins of the anthropocentric political, economic, and socio-technical systems limits the urban forest from being a central part of the built environment.

As an attempt to put urban trees on the political agenda, the USDA Forest Service developed and launched the i-Tree software in 2006 to quantify the ecosystem services provided by urban trees (Nowak, 2020). In 2019, the first version became applicable to the Netherlands. This project is part of the three-year-long follow-up, i-Tree 2.0-NL, consisting of a consortium of 28 stakeholders to further elaborate the cooling performance, model growth curves, and synchronise the potential of the software for the stakeholders. This thesis concerns the latter.

The project starts with an understanding of the overarching transitions, exploring the direction in which the urban green domain should (and currently is) heading to calibrate the compass for change (see Figure 1). The newly proposed paradigm illustrates five societal shifts in how we relate to, integrate, account for, collaborate for and provide access to the urban forest. The ideal is to reposition the urban forest as critical infrastructure. The project is moving towards mapping the current system and processes of the consortium stakeholders, localising the role of the public green sector in urbanisation and discovering interrelationships. The different domains are strategically separated and examined in isolation to explore opportunities for integrating i-Tree into architectural, municipal and nursery processes. From this set of five opportunity areas, the concept of a management dashboard was selected for further development with the aim of linking municipal green space policy and green space management.

The ‘Urban Forest Portfolio’ is created, evolving the use of i-Tree from static assessments to a dynamic portfolio. The dashboard aims to integrate the urban forest lifecycle into planning, management and design, to track progress towards the realisation of long-term quantified targets, and to enable scenario evaluation for just compensation.

The integration of the proposition into the system is discussed, leading to eight concrete new practices and six speculations on a system scale, one of which is the establishment of the ‘Rijksgroenstaat’. Finally, the principles behind these new practices helped to make the new paradigm tangible, operationalise the transitions and bring into focus the parts specific to the domain of this project.

The project aims to discover the systemic granularity of the urban green domain, oscillating between abstract paradigms, concrete practice, and levels in between. A systemic strategy developed side by side with the stakeholders in the green sector.