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Tree Canopy Cover

Variable Definitions:
Existing Tree Canopy Cover: The percentage of area covered by existing tree canopy

Possible Tree Canopy Cover: The percentage of area covered by possible tree canopy

Source:
Tree People 

Years Available:
2016

Why are these variables important to measure?

Tree Canopy Cover

California’s long history of racial segregation and its unprecedented housing crisis has forced urban low-income communities and communities of color to live in segregated urban neighborhoods where housing is generally more affordable (Shonkoff et al., 2011). However, living in dense urban areas places low-income communities and communities of color in close proximity to industrial facilities, oil wells, transit centers, and highways, which increases their exposure to polluted air and elevates their risk of developing respiratory and cardiovascular diseases (Los Angeles County Department of Public Health, 2018). Urban areas are also more likely to experience frequent heat waves and higher temperatures, yet they often lack enough natural greenery to offset the environmental imbalance caused by industrial activities (Shonkoff et al., 2011). Insufficient access to natural land cover and the unaffordability of air cooling systems places low-income urban residents at high risk for heat-related morbidity and mortality (Shonkoff et al., 2011). Urban low-income communities of color thus have to bear the brunt of industrial pollution and climate change.
 
Moreover, studies have suggested a relationship between more tree cover in neighborhoods and better physical and psychological health, better social cohesion, and lower rates of type 2 diabetes, high blood pressure, and asthma (Ulmer et al., 2016). According to the U.S. Environmental Protection Agency (EPA), “Trees and vegetation lower surface and air temperatures by providing shade and through evapotranspiration” (2021). Surfaces shaded by tree coverage can be up to 20–45°F (11–25°C) cooler than unshaded surfaces, and “evapotranspiration, alone or in combination with shading, can help reduce peak summer temperatures by 2–9°F (1–5°C)” (Environmental Protection Agency, 2021). Urban tree canopies also improve air quality by removing pollutants from urban atmospheres at a faster rate (Loughner, et al.) The multiple benefits associated with urban tree canopies go to show that they play an integral role in improving the wellbeing of urban residents.

Citation:

Environmental Protection Agency. (2021). Using trees and vegetation to reduce heat islands. United States Environmental Protection Agency. Link
 
Loughner, C. P., et al. Roles of urban tree canopy and buildings in urban heat island effects: parameterization and preliminary results. (2012). Journal of Applied Meteorology and Climatology, 51(10), 1775–1793. Link
 
Los Angeles County Department of Public Health. (2018). City and Community Health Profiles: Compton. Los Angeles County Department of Public Health. Link
 
Shonkoff, S., et al. (2011). The climate gap: environmental health and equity implications of climate change and mitigation policies in California—a review of the literature. Climatic Change, 109 (S1), S485–S503Link
 
Ulmer, J., et al. (2016). Multiple health benefits of urban tree canopy: The mounting evidence for a green prescription. Health & Place, 42, 54-62. Link

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