The looper invasion

Two looper moth larvae caterpillars munch on hemlock needles in Townsite.

Photo by Sean Percy

BABY MOTHS: Looper larvae south of town, along with their poop. These are Phantom Hemlock Loopers, but the similar Western Hemlock Looper is also ravaging local coniferous trees. Remember the moth swarm last October? It was these two species.

Photos by Sean Percy

It’s raining larvae

Sadly, that’s not the kind of rain qathet needs. Instead, looper moths are infesting the forests in the qathet area, reports associate publisher Sean Percy.

They may kill our trees. And they may not.

Combined with this summer’s extreme weather conditions, they’re not good news.

George Moore doesn’t get anxious easily.

He’s been climbing and falling dangerous trees for a living for over 30 years. As a certified utility arborist, he’s the guy that BC Hydro calls when they need a tree removed near one of their power lines. He doesn’t think twice about swinging from one tree to another, 25 metres off the ground.

But when he looks at the trees around the qathet region right now, “it freaks me out,” says George, who co-owns Powell River Tree Service with his brother Geoff.

As George looks from his home in Edgehill to the hills above Cranberry Lake, he sees swaths of red, where the needles on the hemlock and Douglas fir trees have died. Most of them are suffering from an infestation of Western Hemlock Looper Moths and Phantom Hemlock Looper Moths. When George comes down from a tree these days, the larvae, green inch-worm-like “loopers,” cover his clothing, are tangled in his hair and are crawling under his shirt.

While the moth infestation is particularly bad this year, there’s more affecting the trees than a cyclical pest.

“We’ve been seeing this coming. For at least five years, there has been a serious decline in the canopies.”

In his own yard, he lost three big trees in the last five years “for no reason.” Or at least not a reason that he can be sure about.

Tree mortality is usually attributable to changes in the water table, George says. And with climate change, the stress on the trees is getting worse. The heat wave

in late June that broke temperature records put even more stress on the trees. Then the looper moth eggs hatched and the munching began. The long drought is also having an untold effect.

George’s phone buzzes many times a day with people worried about their trees. He and Geoff and their team have more work lined up than they can handle. A lot of trees are going to die and need to be removed in the next few years. “The ones around houses, you don’t have forever to deal with it. A couple of years after they die, and they have to come down.”

SPOT THE BROWN: A flight over the city in late July revealed the latest summer plague: evidence of looper moth larvae – the brown on the treetops here at Willingdon Beach and Millennium Park.

Photo by Russell Brewer

City officials are also concerned about the fate of trees in Townsite, the Millennium Park forests, Larry Gouthro Park, and elsewhere. When Community Forest staff flew over the local forests in mid-July to survey the damage, City senior administrative officer Russell Brewer, also a forester, went along. What he saw made him concerned. Large areas of forested lands in Townsite and around Valentine Mountain have been hit hard by the loopers.

The operators of Powell River’s Community Forest are similarly concerned about the health of trees in their forest.

“It’s pretty extensive,” says Greg Hemphill, Community Forest president. Last year, the Community Forest adjusted their logging plans, and harvested a hemlock stand that was particularly hard-hit by last season’s looper moth infestation. He expects they may have to do the same this year. Fortunately, the price for hemlock, the species hit hardest, is relatively high, making the logging of trees that succumb to the loopers somewhat more palatable.

“We’re worried, obviously,” says Greg. “Visually, you see it right now. But how much of it is going to die? That’s the million-dollar question.”

In the Tree Farm Licence operated by Western Forest Products, the infestation that damaged trees in the northern part of their tenure seems to have abated, but they’re seeing trees being attacked heavily in the Deer Creek and Conchie areas close to the Community Forest. Hikers and bikers in the Duck Lake area are also dodging looper larvae dangling from the trees – many trees in the park look sickly.

Despite the falling needles and the heightened risk of forest fire, there may be some reason to be hopeful.

Local forester, Eliot King of the Ministry of Forests, says that the energy exchange that happens with looper moths living and dying is a natural cycle. Looper moth poop, which is covering forest floors, is good fertilizer. Moths and larvae are food for birds and hosts for parasitic wasps that protect the forest.

Jeanne Robert, the provincial entomologist with the Ministry of Forests, Lands and Natural Resources, says the looper moth infestation is a natural disturbance that can have a positive effect on forests. Trees that do succumb make way for more diversity in the forest stands. “It looks terrible in the short term, but the mortality is not too, too concerning. Just because a tree loses its needles doesn’t mean it’s doomed. You’ll see them come back over the next few months,” she predicts.

Biologists say this natural cycle of looper moths will crash soon. A parasitic wasp that attacks looper moths usually decimates the blooming population in the third or fourth year of an infestation. What the unusual temperatures, the drought and climate change will do to that cycle remain to be seen. “Climate change makes it more difficult to predict what might happen,” says Jeanne.

Eliot says there’s potential for the damaged trees to recover. We won’t know how well they recover until spring of next year, at the earliest.

This should be the third year of a three-year cycle for the loopers.

“If that’s the case, we can manage it. If that’s not the case, it’s a big problem,” says Greg.

George, the arborist, says he has seen certain species suffer, and then bounce back. Cedars are generally looking better this year than they have in the past few years. “Balsams took a big hit in the late 1990s and have since recovered,” he remembers.

“But this is different. I hope they will come back. But these trees have been fighting for their lives. In my experience, they can only fight so long, and they may have been given a knock-out punch this year. When I go to bed at night, it gives me anxiety.”

Looper in the moth stage of life.

Photo by Sean Percy

Meet the looper moth

Two species of looper moth (or rather, their larval caterpillars) are attacking trees in the qathet region: Western Hemlock Looper (Lambdina fiscellaria lugubrosa) which have a darker green, heavily patterned larva, and Phantom Hemlock Looper (Nepytia phantasmaria) which have a brighter green larva as pictured on Page 20.

Young larvae emerge from late May to mid-June and crawl to the tops of the trees where they start feeding. They’ll form pupa later this month for 10-14 days before transforming into adult moths. The flying moths will swarm around town from late September to early October, when they lay eggs, mostly on hemlock and Douglas-fir trees, before dying off.

According to Natural Resources Canada, outbreaks usually last about three years, after which they are mainly controlled by predators, disease and some of the 47 parasites that may attack the eggs and larvae.

Phantom hemlock looper in the forest-munching stage of life.

Photo by Sean Percy