Seattle's Canopy Cover

Hemlock tree needles

Imagine you were in an airplane flying over the City in summer, as you look down, tree leaves and branches would block your view of some portion of the land below. This tree canopy covers the ground and shades the area below it.  Canopy cover is the percent of the city that is covered by trees, as seen in an aerial view. Canopy cover is an important management tool for the City to understand the extent and distribution of trees in Seattle. Seattle's goal, established in 2007, is to reach 30% canopy cover by 2037, as well as to improve tree health and equitable distribution of trees to support community health and resilience to climate change.  

2021 Canopy Cover Study 

The City of Seattle’s most recent canopy cover study, using data from 2021, found the city lost 255 acres of tree canopy (1.7% relative decline, .5% absolute decrease) since the 2016 canopy cover assessment. Seattle’s canopy cover in 2021 was 28.1%, down from 28.6% in 2016. 
The study also found that:

  • Canopy loss is not happening equitably. Neighborhoods impacted by racial and economic injustice not only started with less canopy but also lost more than the citywide average. While there were some canopy gains in environmental justice priority areas attributed to forest restoration programs, the losses outpaced the gains. 
  • Tree canopy cover is critical for lowering temperatures and reducing heat island effects in our warming climate. Trees are a key component of our climate preparedness and resilience strategies as they protect us from extreme heat and improve air quality. The report finds that at the neighborhood scale, a 13% increase in tree canopy is associated with a .5-degree reduction in temperature. Industrial areas and major transportation corridors have lower canopy and warmer temperatures, as well as smaller areas such as neighborhoods in the Chinatown-International District and in the south end of Rainier Valley. 
  • All Management Units (areas based on land use types) lost canopy, with Parks Natural Areas and Neighborhood Residential areas seeing the greatest net losses. Parks Natural Areas contain 14% of the city’s canopy and saw a relative loss of 5.1%. These areas require active management to ensure long-term forest health and resilience, and losses here may be due to aging deciduous trees coming down naturally or being selectively removed to allow for growth of evergreen trees.  
  • Neighborhood Residential areas contribute nearly half of the City’s canopy (47%) and saw a relative loss of 1.2%. A small percent of residential land underwent development during the study, but canopy losses were high on those properties. Most trees on residential land were likely lost due to reasons other than development. Combined, losses in these two Management Units comprise 78% of the total canopy loss during the assessment period. 

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