KING COUNTY, Wash. —

As western Washington summers become warmer and drier, King County is working to make sure forests that are adapted to wetter and colder conditions can still thrive. 

“We know that climate change is coming,” said Paul Fischer, King County forester. “We are already seeing hotter, drier summers, and we want to find trees that are adapted to hot, dry summers.” 

The county’s Department of Natural Resources and Parks planted seedlings in four different test fields around different parts of King County. Those seedlings are the same species already found in western Washington, but from trees that grow in warmer, drier neighboring areas including southwest Washington, Oregon and northern California. 

The project team selected Douglas fir, western redcedar, Sitka spruce, grand fir, western hemlock, and ponderosa pine species for the study. 

“If our conditions are changing, maybe we can source seeds that are genetically adapted to hotter, drier conditions but they’re the same species that we grow here,” said Kathleen Farley Wolf, King County Forest Conservation director.

The team spent years looking at projections for how Western Washington’s climate might change through the year 2100. They found regions in the Pacific Northwest that matched those projections and pulled seeds from those trees. 

They planted the seedlings in lines to have a clear look at which grows the fastest and best. The team estimated having a good idea within a few years of which tree species from which regions will do best. They will keep monitoring for the next decade, though. 

“So they need to be able to survive our wet and colder winters but hopefully can also do better in these drier summers of the future,” Farley Wolf said.

After they figure out what species are best, the goal is to plant those throughout the 28,000 acres of forestland in King County. 

“For me, this is one of the most fun projects to work on,” Wolf said. “I think we can hear a lot of negative things about climate and it can cause people a lot of anxiety. This is a way we can say, ‘Okay, how can we set our forests up for the future? How can we set them up to be resilient?'”