*5.4. Research Theme*

The literature reviewed in this study found a strong emphasis on research addressing human needs and values as well as those addressing the planning, design, and management of urban greenways. Constituting roughly three quarters of all studies reviewed, this is not surprising: urban areas are, by definition, dense agglomerations of people and cities are inherently complex and contested settings that require nuanced planning and management. What is perhaps a bit surprising, is the relatively limited body of scholarship explicitly addressing environmental issues (classified here as *physicality*). This is especially noteworthy considering the strong ecological foundation that undergirds conceptualization of greenways writ large, as noted in the introduction to this paper [1,5,17,19].

It should be noted, however, that many studies did address environmental concerns but they also included social dimensions, whereby they were classified as interdisciplinary. For example, Larson et al. [57] examined how the public perceives ecosystem services of urban greenways and found that people value cultural benefits, such as social gathering and recreation more than environmental functions. This reinforces the need for thoughtful planning and design and striking a balance between programmed/unprogrammed and naturalistic/hard-scaped spaces.

Other studies embrace a socio-ecological approach that addresses both people and the environment, such as benefits that urban greenways provide for mental health and biodiversity [58], and greenways

as strategies for urban sustainability [59–61]. For example, one study found that for residents living near a newly installed greenway, greenhouse gas emissions decreased by 20.9% after the greenway's construction and the change in emissions was attributed to a reduction in vehicle kilometers traveled enabled through provision of high-quality active transportation infrastructure through cycling facilities and other streetscape improvements [44].

It is a bit surprising that there are not more studies addressing the economic dimensions (classified here as *valuation*) of urban greenways. As noted by some studies in the literature reviewed, urban greenways can increase adjacent property values [62,63] and employment density [33]. This can, in turn, be harnessed to finance greenway management through the creation of business improvement districts, exemplified at the Rose Kennedy Greenway in Boston [64]. On the other hand, new green spaces can lead to gentrification and displacement of local residents [65,66]. This tension is ripe terrain for expanded research on urban greenways.
