ANACORTES — A group dedicated to understanding how the Anacortes Community Forest Lands are changing and may continue to change as the global climate warms has its first insights from data gathered by volunteers.
The Fidalgo Forest Stewards have since May spent 300 hours documenting tree and shrub species — and their health — for the new Anacortes Community Forest Lands Monitoring Project.
Volunteer coordinator Jack Hartt said 41 are involved in the project, which is organized through the nonprofit Transition Fidalgo & Friends and the city of Anacortes, and has plans to expand in 2020.
Early results from surveying trees near Whistle and Heart lakes and documenting the health of Western red cedars along about 4 miles of trails have confirmed that recent summer drought conditions have impacted tree health.
“There has been a visually observable and quantifiable increase in drought-caused stress and mortality in cedars and hemlocks,” said University of Washington forest scientist Dave Peterson, who is involved with the project and helps train volunteers. “Long-term monitoring will allow us to detect future changes in forest conditions, and it will be especially interesting to track the effects of future droughts, which are anticipated to occur more frequently in a warmer climate.”
Western red cedars and Western hemlocks have been dying throughout Western Washington likely in response to drought conditions or because of drought conditions combined with fungal or insect attacks.
“We continue to see widespread impact of increased temperatures, decreased summer rainfall, and decreased winter snowpack,” said area forester Kevin Zobrist, a professor in the Washington State University Extension forestry program.
Peterson said the impacts in Skagit County to cedars and hemlocks is likely most severe in the Anacortes Community Forest Lands because the area receives less rain than other parts of the county and its soil dries quickly.
“We can think of the Anacortes Community Forest Lands as a ‘canary in the coal mine’ for the broader forest landscape,” he said.
In the 2,800-acre city-managed forest, volunteers studied trees at six survey sites near Whistle Lake and at six survey sites near Heart Lake. Their work will be repeated each summer to build a long-term data set.
Near Whistle Lake, they found that 39% of Western hemlocks and 23% of Western red cedars were dead — numbers Peterson said is high.
While dead trees are an important part of any forest because they provide habitat and nutrients for future generations of plants, Peterson said about 10% would be considered normal.
The high percentage of dead trees in that area, combined with evidence that many died within the past two years, supports the idea that drought has had an impact, according to a data summary.
About a mile away, near Heart Lake, a portion of the forest studied by volunteers appeared healthier.
Peterson said that’s likely because the survey sites there are at the base of a incline, where soil moisture is better retained during the summer than at the sites near Whistle Lake.
Over time, the forest near Whistle Lake may become more dominated by Douglas fir — similar to the forest near Heart Lake — as cedars and hemlocks continue to die.
The volunteer program was formed after city staff, members of the nonprofit Friends of the Forest and community members who hike in the forest lands noticed the foliage of increasing numbers of cedars turning from green to orange as the trees died.
Hartt wrote in a summary of the work done in 2019 that ongoing data collection will allow scientists and land managers “to see the changes in black and white as well as green and orange.”
In addition to the work surveying and comparing forest health near Whistle and Heart lakes each summer, the group is surveying cedars along trails and gathering photos of a Little Cranberry Lake burn site to document its recovery.
Hartt said the trail-side surveys have identified about 100 cedars to track in a variety of habitats, which will offer more insight about the lives and deaths of the trees in different areas over time.
The group involved in the monitoring project doesn’t intend to stop there.
In 2020, it plans to add at least two more study components — examining water and when the buds of plants break.