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A micro-forest at the University of Washington Tacoma contributes to the university’s mission and to ongoing efforts to enhance and improve our urban tree canopy in Tacoma. It arrives at a time when the city is growing and building density while simultaneously realizing that our scant tree canopy puts many of our residents in peril in the era of climate change.
A 2011 analysis conducted by UW students (sponsored by the DNR and Community Forestry Program concluded that “Tacoma’s tree canopy covered approximately 19% of the city’s land area” (Tacoma Canopy Cover Assessment). A subsequent 2018 study conducted by the King County Conservation District (sponsored by the USDA Forest Service Urban and Community Forestry Program) concluded that Tacoma’s 20% of land area coverage made it the city in Puget Sound with the “least amount of tree canopy” in the region (Urban Tree Canopy Assessment).
The lack of tree canopy does not impact all residents of Tacoma equally. The 2018 report further concludes that, “within the city of Tacoma, tree canopy is not distributed evenly, with some census blocks experiencing as low as 3% tree canopy cover, while others have as high as 64%” (Urban Tree Canopy Assessment). To overlay the tree canopy distribution map of Tacoma over Tacoma’s equity index map is to realize that the city’s lack of tree canopy is a matter of environmental justice, as those areas of Tacoma which the least amount of tree canopy (and its associated health impacts, including the heat island effect and poor air quality) are the very same areas of Tacoma that have been impacted by various forms of structural racism and other forms of oppression.
There are many approaches to growing and improving the tree canopy in cities (also known as afforestation). Micro-forests are one promising approach as these grow faster and become semi-self-sustaining in just two to three years. This micro-forest is built partly on a method developed by the late Japanese botanist and ecologist Akiro Miyawaki. His technique, developed through his study of potential natural vegetation, phytosociology, and the sacred shrine forests important within the Shinto tradition, calls for layering a forests with native plants in this manner: a main tree species, then shrubs, then ground cover, then herbs.
The micro-forest at UW Tacoma blends the Miyawaki Method with other forms of managed landscapes, particularly the camas prairie, a type of landscape that was practiced by Coast Salish people in this area for many, many years. Often anchored by Garry Oak (Quercus garryana), these prairies were populated with shrubs and medicinal and edible plants, namely camas (Camassia quamash/ċabid or ċabidac in Lushootseed).
