Navigating the Future of Metropolitan Trees

Abstract

Urban populations are rising all over the world. According to the United Nations 60% of global populations is projected to live in urban area’s by 2030. The formation of the urban heat island effect (UHI) and it’s impact on human health and well-being by the increase of heat stress in hard surfaced urban area’s has been described and measured by a multitude of studies. (Oke, 1989) The cooling ability of urban green infrastructures (Pauleit et al., 2020) with trees in particular is currently widely acknowledged. (Rahman et al., 2020). However, planting trees in city centres where they are most needed for a healthy and sustainable living environment still remains a challenge due to extreme growth conditions (Sjöman et al., 2018). Densely populated urban area’s are constantly developing and due to the limited above and underground space new planted trees rarely reach maturity. In addition the underground utilities with frequent maintenance, soil compression and the lack of nutrients further complicate healthy and consistent growth of tree canopies. (Ferrini et al., 2019) If we want our trees in the hardscaped everchanging urban environments of city centres to provide many of its benefits for the next generation, the technical design for planting, maintaining and strategically locating trees in urban area’s should be reassessed now.