Urban Forest Canopy Cover
Type of content
Tree canopy cover (TCC) is the total area of tree crowns projected onto the ground. It expresses canopy area as a percentage of total ground area. TCC is commonly used to describe the amount and horizontal distribution of urban forest canopy within a given city. It is commonly used by various stakeholders, including local authorities, urban foresters, arborists, planners, urban designers, and developers. Because tree canopy cover has been linked with ecosystem service provision and benefits for local communities, various cities around the world have set targets to increase their urban forest canopy cover. However, these global TCC targets largely appear to be aspirational, rather than being justifiably informed by current research. This technical report uses a comprehensive review of the grey and scientific literature to answer the question of how much tree cover is desirable, or appropriate, in the context of New Zealand’s cities. Results show that research no longer supports a universal tree canopy cover recommendation. Instead, different canopy cover targets should be tailored to individual cities, based on local context. Based on TCC reported by 124 cities around the world, as well as previous research findings, target canopy cover ranges for NZ cities were devised. Cities within forested biomes, which cover much of New Zealand, should aim for a TCC target of 25% (± 20%), or between 20% – 30%. Meanwhile cities within grassland biomes, mainly comprising parts of Canterbury, Otago, and Southland, should aim for a TCC target of 20% (± 20%), or between 16% – 24%. The recommended target ranges do not preclude cities from aspiring to greater canopy cover, though overly-ambitious targets may be unachievable and undesirable for a variety of reasons. The international literature also shows that some cities are moving away from setting a single, city-wide, target, opting instead for different targets across electoral wards, local boards, neighbourhoods, or land uses. This technical report concludes with eight recommendations to successfully meet canopy cover targets, including identifying baseline canopy cover, setting a SMART tree canopy cover target, monitoring changes in TCC, institutionalising targets in a strategy or management plan, having a vision, identifying plantable space, identifying and mitigating threats to increasing TCC, and forecasting future urban TCC scenarios.
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Fields of Research::30 - Agricultural, veterinary and food sciences::3007 - Forestry sciences::300703 - Forest ecosystems
Fields of Research::41 - Environmental sciences::4102 - Ecological applications::410204 - Ecosystem services (incl. pollination)