Warm, dry summers taking toll on area trees, plants
Throughout some of Skagit County’s traditionally lush, green forests, some trees and leaves are turning brown — a sign of plants starved for water and in distress.
Foresters, forest advocates and public lands managers are seeing this in areas from Anacortes to Mount Vernon after several summers that were hotter and drier than normal.
Western red cedars, sword ferns and salal are some of the species that have dried out during the past several summers, in some cases making them more vulnerable to disease.
“This is the time of year when sword ferns are typically lush and green and happy,” Denise Crowe, former education and outreach director for the nonprofit Friends of the Forest, said while walking along a trail near Heart Lake in the Anacortes Community Forest Lands.
Crowe has spent much time in the Anacortes Community Forest Lands over the past 30 years.
What she’s seen in the past few years are dying trees and plants that stand out in contrast to the greenery of still-thriving plant species.
The Anacortes area nonprofit Transition Fidalgo & Friends plans to start monitoring those changes in the spring.
Kevin Zobrist, a forestry professor at Washington State University Extension Forestry, said issues with trees dying have worsened in the past year.
“We are seeing elevated levels of die-off throughout Western Washington,” Zobrist said. “I think I’ve had more people contact me about dead trees in the past year than the past 10 years combined.”
About 100 community members packed into the Mount Vernon City Library on Wednesday to hear Zobrist explain what’s happening.
Most in the audience raised their hands when Zobrist asked whether they’d noticed cedars in the area turning brown. Several asked questions about trees on their properties.
Zobrist said forests are constantly changing, and brown leaves or needles and some dying trees are not necessarily bad for overall forest health.
He said he often receives exaggerated reports of tree die-offs and false reports of insect infestations, but what is happening with area cedars is a real emerging issue.
It’s also likely to continue as the climate changes.
“One of the things we’re seeing more recently are the impacts of climate change stress, particularly with summers that are getting warmer and drier,” Zobrist said. “We have water stress now.”
As the global climate warms, higher temperatures will bring more frequent drought conditions, according to the National Climate Assessment released in November.
That report concluded that climate change will reshape forests throughout the country through increased wildfires, intensified insect infestations, and changes in the abundance and distribution of some species.
“More dead trees on our properties, on our landscape, is going to be the norm,” Zobrist said. “We have to learn to tolerate that.”
A REGIONAL ISSUE
Dan Omdal, forest pathologist for the state Department of Natural Resources, said Western red cedars dying because of recent hot, dry summers is primarily being seen in Western Washington, where the trees are common and are accustomed to ample rain.
“The western red cedar is what I call a thirsty tree,” Omdal said. “It does well when there is lots of water.”
He said he has recently been called to examine cedars dying in local areas including at Lake Campbell near Anacortes, in Little Mountain Park in Mount Vernon and on private properties.
“It was a hot and dry summer and as we were digging in the soil it was just powder,” Omdal said of when he assessed the Lake Campbell trees earlier this year.
When the soil dries out, trees such as cedars can become stressed and are more susceptible to diseases or insect infestations.
“It’s amazing that water can mask a multitude of ailments,” Omdal said. “As long as you keep pouring water on the tree, then it can look fine even though it might have a pathogen nibbling on its roots or a fungus growing on its stem.”
He compares these types of attacks on tree health to cold and flu viruses that threaten human health.
Like viruses that may be floating in the air or clinging to door handles, fungi and pathogens in the soil are often unnoticed. Trees that get enough water are better able to fight off disease, similar to how a person with a healthy immune system may be able to avoid getting sick.
While investigating dying western red cedars in Skagit County and surrounding areas, Omdal said he found cases of where the trees were solely impacted by a lack of water and cases where that lack of water enabled diseases to take hold.
MORE CHANGE AHEAD
If the die-off of cedars, ferns and other impacted species in the area is severe enough, it could lead to long-term changes in the makeup of area forests.
As vulnerable species such as cedars die off, they can leave open spaces that could be filled by nearby native species or invasive species.
“When we start getting these shifts in the norm, you’re going to have some species that do well and some that do not, and then a decrease in diversity over time,” Crowe said.
Dan McShane, a geologist who lives on Samish Island, said he suspects that could happen throughout western Skagit County.
Hot, dry conditions pose a particular risk to cedars and other trees in shallow soil, which is common in low elevation areas throughout the region.
Crowe said because shallow soil is characteristic of much of the Anacortes Community Forest Lands, the presence of cedars will likely decline throughout Fidalgo Island.
“The trend is that there will be a lot fewer western red cedars growing in this area,” she said.
Jack Hartt, who was the manager of Deception Pass State Park for 14 years, said he believes the same issues will affect the forests in that area, where he has also observed cedars turning brown.
“My concerns are the bigger-picture issues, that these things are indicating that the entire planet is changing and we just don’t know what that means ... for future generations,” Hartt said. “We’re seeing changes here and we’re seeing changes all over the world, but what are we going to do about it?”
Transition Fidalgo & Friends believes tracking the changes is a good place to start.
The organization is working with the Anacortes Parks and Recreation Department and others in the community to organize a volunteer citizen science research project to do that in the Anacortes Community Forest Lands.
Anacortes Parks and Recreation’s forestlands manager Jonn Lunsford said the city has seen cedars dying in city-managed forests in the Anacortes Community Forest Lands, Washington Park and other areas.
“It is possible the citizen science project with Transition Fidalgo will help us learn more about what is going on here,” Lunsford said.
Transition Fidalgo wants to help gather data to document how widespread and long-lasting the changes are in the forestlands.
“Anecdotally, we’ve had a number of people saying they are noticing changes in our forests already,” Transition Fidalgo board member Eric Shen said. “A lot of young seedling trees are not making it simply because it is too dry in the summer.”
He said the goal of the monitoring project is threefold: to inform community members about what’s happening in area forests, to build a scientific data set that may reveal emerging impacts of climate change and to help guide management of the forests.
Crowe said she supports the project and is eager to see whether it leads to potential solutions.
“It’s not like we can go around the forest watering all the western red cedars,” Crowe said. “How do we solve this problem? It’s vast.”