Hellish tree, insect threaten to ‘decimate Washington’s crops’ | Wild Neighbors

By Scott Doggett
Posted 9/4/24

With its sunset-colored seeds, quill-shaped leaves and silvery trunk, the tree of heaven doesn’t emit a threatening vibe.

But then neither does a tiger. If you knew nothing about tigers …

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Hellish tree, insect threaten to ‘decimate Washington’s crops’ | Wild Neighbors

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With its sunset-colored seeds, quill-shaped leaves and silvery trunk, the tree of heaven doesn’t emit a threatening vibe.

But then neither does a tiger. If you knew nothing about tigers and saw one strolling down the street, no one could blame you if you approached it for a closer look.

Indeed, the tree of heaven (Ailanthus altissima) is famous in its native China for its beauty. And its name could not be more divine. But make no mistake: It’s a killing machine.

Tree of heaven grows as fast as bamboo, creates thickets that starve native plants of sunlight, excretes toxins that poison competitors, and rapidly multiplies by cloning itself via underground suckers and by seeds that scatter like confetti.

If you chop down a tree of heaven without also applying a particular herbicide, dozens of clones will sprout from its roots. I know. I had a tree of heaven on my property years ago, took an ax to it, and within weeks 40-plus clones replaced it. 

But that’s not all. The tree is the preferred host to the spotted lanternfly, a swarming insect from China that “could be one of the most harmful pests in our generation,” said Sven-Erik Spichiger, managing entomologist for the Washington Department of Agriculture.

And to quote Eric Bell, who heads the noxious weed control board of Washington’s Adams County, a farming community an hour’s drive southwest of Spokane, “there’s no stopping the spotted lanternfly.”

The insect, which secretes a sugar-rich liquid that causes sooty mold fungi to grow on grapes, tree fruits and other crops, making them unmarketable, arrived in America in 2014. It was first discovered in Pennsylvania and now occupies 17 Eastern states.

At least two of the bugs have made it to the West Coast. Both were dead on arrival when they reached Oregon from Pennsylvania in shipping containers four years ago.

Bell told me there’s no ridding Adams County of its trees of heaven. There are just too many of them. So, he spends his days writing, calling and making in-person appeals to Adams County residents, urging them to contain the trees’ spread “by removing saplings and seedlings as well as small trees if they can.”

Bell’s hope is that the spotted lanternfly will find few trees of heaven in Adams County and move on. Unless he’s given the authority to require property owners to remove the trees, it’s the best he can hope for. 

Bell could receive that authority from the Adams County weed board, but to quote a state official close to the subject, “county officials don’t want to do enforcements on their neighbors.” 

Removal of a single large tree of heaven can cost thousands of dollars. The per capita income in Adams County, where agriculture is the top industry, is less than $17,000. Bell said that if he required property owners to remove trees, “I’d be hung from one.”

Bell was one of five people I spoke with last week who are knowledgeable about the tree of heaven and the spotted lanternfly. All five said the insect will reach Washington — assuming it’s not already here.

“The tree of heaven and spotted lanternfly have the potential to cause massive economic damage to Washington,” Anne Schuster, education specialist for the Washington State Noxious Weed Control Board, told me. “Together, they could decimate Washington’s crops.”

The tree of heaven exists in Jefferson County, as it does in most of the state. Huge specimens cover a bluff above Port Townsend’s historic district, the species is spreading south of the district along Water Street, and it can be found above the bluff, in the Uptown area.

Jefferson County’s noxious weed control board coordinator, Sophie DeGroot, said the board “will continue to follow the state’s lead and when the time comes to require its control, we will do so.”

That said, in an email to me DeGroot wrote that Jefferson County’s weed board, which consists of three voting members, “could require people to ‘control’ their trees.”

“This could be in the form of removal of the whole tree or simply killing the tree but leaving it in place if needed for economic or stabilization reasons,” she wrote. “As long as the tree is not producing seeds or sending out vegetative shoots, it has been ‘controlled,’ ‘contained,’ ‘eradicated,’ and is preventing the further spread of the noxious weed,” in accordance with the law.

There’s no doubt that the huge trees of heaven in Port Townsend’s historic district stabilize the bluff, just as there’s no doubt that they disperse thousands of seeds every summer. 

It should be noted that Jefferson County occupies 2,183 square miles — enough space to contain 95 Manhattans plus several Silverdales. It should also be noted that DeGroot is monitoring more than 100 noxious weeds, not just the tree of heaven.

Remarkably, Jefferson County provides funding for only one full-time weed control employee — DeGroot — and one part-time seasonal employee. 

But there’s cause for hope. In the September 2020 issue of “Biological Control,” researchers at Virginia Tech reported that they had isolated a microscopic organism that proved highly effective in killing the tree of heaven when injected into its trunk.

I reached out to the report’s author, Rachel Brooks, who’s now a forest pathologist for the Washington Department of Natural Resources. I wanted to know how close the fungal pathogen was to being marketable. 

Brooks said research is ongoing between the U.S. Forest Service, universities and a business to finalize the work needed to get the Environmental Protection Agency to approve the biopesticide. 

It’s a lengthy process because the U.S. is very risk-averse to biological control agents following some historic failures, and therefore extensive research is required to get a biological control through the system and approved, Brooks said.

Continuing, she said that “there have been no results that have indicated that the product wouldn’t work or be safe to use.” 

Right on.

Scott Doggett is a former staff writer for the Outdoors section of the Los Angeles Times. He and his wife, Susan, live in Port Townsend.