Why Do Urban Forests Matter?

Urban forests provide city dwellers with many ecosystem services, or benefits that humans derive from nature. (Dialy, 1997)

For example, well-planned, well-managed urban forests have the potential to:

• Contribute to the physical and mental health of urban dwellers by buffering stress, creating inviting places for physical activity, and more (Braubach et al, 2017; Sanesi, Gallis, & Kasperidus, 2011; Wolf & Robbins, 2015)
• Mitigate the heat island effect by reducing temperatures through shading and evapotranspiration (Lai et al, 2019; Nowak, Dwyer, 2007; Sanesi, Gallis, & Kasperidus, 2011)
• Reduce burdens on traditional water infrastructure and reduce run-off by absorbing and filtering stormwater (Kuehler, Hathaway, & Tirpak, 2017)
• Calm traffic and reduce driver speeds when properly incorporated along roads and rights-of-way (Mok, Landphair, & Naderia, 2006; Wolf, 2010)
• Improve air quality by removing harmful pollutants, like particulate matter, ozone, and smog, in certain contexts; however, trees may also trap air pollution in urban canyons, create allergenic pollen or even emit pollutant precursors (Kumar et al, 2019; Sicard et al, 2018)
• Reduce noise (Nowak & Dwyer, 2007;  Sicard etl al, 2018)
• Improve scenic quality and aesthetic appeal (Nowak & Dwyer, 2007)
• Support local livelihoods and provide fuelwood, medicine, and other goods (Sanesi, Gallis, & Kasperidus, 2011)
• Enhance community cohesion by fostering social interaction, building environmental consciousness, and establishing a shared sense of place (Sanesi, Gallis, and Kasperidus, 2011; Weinstein et al, 2015; Wolf, 2017)
• Increase food security for marginalized populations in both developed and developing contexts (Braubach et al, 2017; Konijnendijk & Gauthier, 2006; Kowalski & Conway, 2018)
• Enhance agricultural productivity in peri-urban agroforestry by improving site conditions and diversifying production for smallholder farmers (Konijnendijk & Gauthier, 2006)
• Sequester carbon; however, pruning, fertilization, and irrigation of street trees may also result in CO2 emissions (Nowak et al, 2002)
• Increase property values and thus increase municipal tax revenue. In some cases, trees may also impose financial burdens on landowners related to tree care or removal or taxes related to property value or contribute to displacement of vulnerable groups (Nowak & Dwyer, 2007; Aguelovski et al, 2019)
• Increase residents’ connection to nature during resident engagement activities such as tree plantings, which may promote other pro-environmental behavior (Whitburn, Linklater, & Milfont, 2019)
• Increase equity, as benefits from urban greening can be most impactful for disadvantaged groups (Braubach et al, 2017;Wolf, 2017)
• Intercept rainfall and surface runoff to reduce erosion and sedimentation in urban areas and along coasts and streams (Berland et al, 2017)