Understanding opportunities for urban forest expansion to inform goals: Working toward a virtuous cycle in New York City

Abstract

Urban forests are critical infrastructure for mitigating environmental and social challenges cities face. Municipalities and non-governmental entities, among others, often set goals (e.g., tree planting or canopy targets) to support urban forests and their benefits. We develop the conceptual underpinnings for an analysis of where additional canopy can fit within the landscape, while considering factors that influence where trees can be planted, and canopy can grow (“practical canopy”). We apply this in New York City (NYC) to inform the setting of a canopy goal by the NYC Urban Forest Task Force (UFTF) for the NYC Urban Forest Agenda, which may trigger a virtuous cycle, or a positive feedback loop where people are mobilized to protect the urban forest, and its benefits that ultimately motivate people to commit to its conservation. We further develop framing for a “priority canopy” analysis to understand where urban forest expansion should be prioritized given more context (e.g., environmental hazards and local preferences), which can inform how expansion of the urban forest is achieved. We estimate an opportunity for 15,899 ha of new canopy in NYC given existing opportunities and constraints (practical canopy), which, if leveraged, could result in nearly doubling the canopy as of 2017 (17,253 ha). However, like existing canopy, practical canopy is not evenly distributed, in general, or across jurisdictions and land uses. Relying solely on areas identified as practical canopy to expand the urban forest would exacerbate these inequities. We discuss how the NYC UFTF established a visionary and achievable goal of at least 30% canopy cover by 2035, informed by this analysis and guided by priorities of equity, health, and resilience. Achievement of this goal will ultimately require a combination of protecting and stewarding the existing resource, and leveraging opportunities for tree planting. Achieving a more equitable urban forest will also require identification of priority canopy, and, in cases, creation of new opportunities for tree planting and canopy expansion. Overall, the collaborative establishment of such goals based on local context can be instrumental in creating a virtuous cycle, moving conservation actors toward exercising influence and agency within the social–ecological system.

High-Resolution Modeling of Summertime Biogenic Isoprene Emissions in New York City

“…NYC has established a citywide goal of equitably reaching at least 30% tree cover by 2035. NYC has the potential to increase citywide tree canopy cover from 22% to 42% without changing existing landscape constraints . On a borough level, the potential for increasing canopy cover is greatest in Queens (from 19% to 43%) and the smallest is in Manhattan (from 21% to 29%).…”

“…On a borough level, the potential for increasing canopy cover is greatest in Queens (from 19% to 43%) and the smallest is in Manhattan (from 21% to 29%). The Bronx (from 25% to 42%), Brooklyn (from 18% to 32%), and Staten Island (from 31% to 59%) are in between …”

“…The Bronx (from 25% to 42%), Brooklyn (from 18% to 32%), and Staten Island (from 31% to 59%) are in between. 34 We use NYC-MEGAN and the box model to evaluate the influence of different urban greening scenarios (i.e., variations in species planted) on future isoprene emissions and air quality with a focus on examining peak ozone concentrations. We implemented two different urban greening strategies in NYC-MEGAN to estimate the potential increases in future isoprene emissions: (i) we increased tree canopy cover by expanding tree canopy extent on a borough level while keeping tree species composition unchanged; (ii) we increased tree canopy cover by expanding tree canopy extent on a borough level and assumed the additional canopies are oak.…”

“…NYC established a citywide goal of equitably reaching at least 30% tree canopy cover by 2035 (The New York City Council, Int 1066−2023) motivated by the ecosystem services provided by trees (e.g., CO 2 mitigation, 31 water interception, 32 and heat mitigation 33 ) as well as by city beautification and increased property values. Treglia et al 34 suggest the existing NYC landscape could support 159 km 2 of additional tree canopy, doubling the current canopy cover of 22% (as of 2017) to 42% of the land area. There is rapidly growing interest among urban planners to favor planting native species because they support native biodiversity.…”

“…NYC has the potential to increase citywide tree canopy cover from 22% to 42% without changing existing landscape constraints. 34 On a borough level, the potential for increasing canopy cover is greatest in Queens (from 19% to 43%) and the smallest is in Manhattan (from 21% to 29%). The Bronx (from 25% to 42%), Brooklyn (from 18% to 32%), and Staten Island (from 31% to 59%) are in between.…”