Yellow Island Preserve

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Owned and managed by The Nature Conservancy, this 11-acre island lies between Orcas and San Juan Islands in the Puget Sound. For the last 30 years it has been the site of extensive research and repeated controlled burning to mitigate the invasion of grasslands by woody species.


A Diverse (and Micro) Ecosystem

Yellow Island has an unusual diversity of native plants, largely due to its isolation and lack of agriculture or historical grazing practices. Nearly treeless at the beginning of the 20th century, Douglas fir and invasive plants steadily encroached until the 1980s when The Nature Conservancy began targeted restoration efforts with prescribed fire.

Photos 1-2 and 3-4 are before and after pairings showing the visible impact of controlled burns on grasslands and wildflowers, and when combined with mechanical removal, the eventual reversal of Douglas fir invasion. 

Defending Prairies and Grasslands 

Fir trees and shrubs often aren't viewed by the public as invasive species, but it's largely because they've been so incredibly successful at establishing residency in Western Washington prairies and grasslands. Converting prairies to agricultural use and suppressing their natural fire regimes nearly guaranteed this invasion. Today, only 3% of a former 150,000 acres of Washington prairies remain, and those areas that do exist are small and fragmented from one another. 

Using prescribed fire to restore prairies and grasslands is vital to overall ecosystem health. And it's also complicated, because so many fragile, threatened species call these areas home. Using the right fire, in the right place, at the right time is always important, but especially here.

Visit South Sound Prairies to learn more.