Spruce Bark Beetles: Scourge of Southern Alaska
Originally printed in Lonely Planet Alaska 7 (2002)
The strongest spruce trees, those that have remained green an extra season even as the 85% to 98% mortality rate among them takes its toll, seem to be weeping. Those that can resist the growing infestation of spruce bark beetles do so by forcing the insects’ eggs from within their wounded trunks with an outpouring of viscous orange sap, pouring in rivulets toward the desiccated earth.
The spruce bark beetle (Dendroctonus rufipennis Kirby) has been a part of the Alaskan ecosystem for thousands of years. But the insects have always preyed upon the weak, raising clutches of up to 1500 eggs inside trees long past their prime. It was part of nature’s great cycle, and trees too old and dry to make the investment of water and energy necessary to flood the nests with life-saving sap would die.
Infected trees weaken the first year of the infestation, their needles growing brittle and red as the growing larva devour their soft vascular tissue, denying them sustenance. By the second summer, they are reduced to gray skeletons, allowing light to reach the tender saplings on the forest floor. And so it was, by the efforts of this tiny beetle, that the Alaskan forest remained healthy and green.
Then, in the late 1980s, something went terribly awry in the far southwestern corner of the Kenai Peninsula. Some blame fire suppression, others the construction of a new dam that seemed to spur the outbreak, while still others point to global warming: Long, dry summers unlike any this land has seen since before the last ice age are dramatically altering the Alaskan environment. The official explanation, half-heartedly repeated by USFS rangers, is that even this holocaust of spruce is part of nature’s great cycle.
Every 250 years, they say – though evidence is sketchy at best – the beetles perhaps receive some cosmic mandate to take down Alaska’s spruce forests entirely. The beetles’ maturation period shortens, their numbers multiply and on that one day every spring when untold millions take flight simultaneously, another 50,000 acres of protected forest will fall. And so the spruce trees have fallen, making room for the alder and birch so beloved by moose, ptarmigan and arctic hair. “Nature is not being destroyed,” explained one forest ranger. “It is simply changing.” Fair enough.
Yet, even as these lines are dutifully repeated to visitors shocked by the endless gray forest expanse, a collective American memory surfaces. Chestnut blight. Dutch elm disease. Casualties in the largest mass extinction since the dinosaurs, which just happens to coincide with the accelerating Industrial Revolution.
Dead trees cannot decay quickly here on the border of the Arctic Circle, it is simply too cold for termites and their ilk. Thus, thousands upon thousands of acres of kindling, every tinder-thin branch still in place, surround villages and homes. When the fire comes – no one ever says “if” – it could be enormous. These hollowed husks burn hot, and their branches burn close to the ground, not the like the ordinary blaze of a healthy climax ecosystem.
When the infestation first began spiraling out of control on the Kenai, the USFS recommended cutting a wide swath through the national forest – a spruce-bark-beetle break, if you will. National – but not Alaskan – environmental groups protested, and the rangers’ requests were denied. They tried to control the outbreak in other ways, like baiting “fall trees” to lure the insects away from their healthy neighbors, but it didn’t work. Today, the infestation has spread to far to pretend that any human endeavor could contain it.
If you drive the Sterling Highway through the western half of the peninsula, you’ll see recently approved cuts in the once sacrosanct national forest, strategically placed so that fire crews might more easily contain the prophesied inferno. Homeowners are clearing the very woods that lured them to Alaska in the first place. And still the beetles spread north to the Chugach Mountains, Denali National Park and dry – the beetles do best where it’s dry – Anchorage Bowl. And south to Canada.
No amount of weeping for what has already been lost will moisten the earth enough to derail these forests’ unsettling destinies, but there are ways you can help. Be careful with your campfires and cigarettes. Do not transport wood outside the hot zones. And if you found solace in these forests before, when they were lush and green and all seemed to be in balance, keep those memories precious. This place may not know such beauty again within our lifetimes.