|Cold winters protect the pines from beetle infestations.|
The Rocky Mountain seasons and winter snowpack have also done their part in maintaining the balance between beetle and pine. Cold winters – with occasional cold snaps reaching 30-40 degrees below – would reliably wipe out 80% of pine beetle larvae. And cool summers would assure prolonged snow melt, providing moisture to keep the pines healthy during their summer-long struggle against the manageably-few surviving beetles.
But something’s changed in the Mountain West: From Arizona to British Columbia the pine beetles are going nuts. And the pine forests are suffering unimaginable devastation.
|A lifetime’s work: Furnish observing still-healthy forests|
What Furnish is describing is a pine-forest die-off of epic proportions. Pine beetles are overwhelming the forest defenses, resulting in rust-red dead pines almost beyond measuring. The scale is astounding: The dead or dying forests cover an area in North America the size of Wisconsin; or for easterners, the combined areas of Virginia and Maryland. You could fit five New Jerseys into the beetle kill zone.
And while foresters like Furnish can attest to the freak nature of the infestation in recent history, researchers have traced the record back much further. According to British Columbia analyst Ben Parfitt, the forest die-off “is probably the biggest landscape-level change since the Ice Age.”
Apparently, God’s symphonic masterpiece has begun playing out of tune. What happened?
|Not autumn colors: The red is dead. Gray/white skeletons died earlier|
There’s actually not all that much mystery. The climate in the West has been undergoing sustained changes not seen in tens of thousands of years. The average winter lows in much of the Mountain West have warmed by 4-6 degrees in the last half-century. The cold that used to reliably kill off most pine beetle larvae every few years “just doesn’t happen anymore,” says Steven Running of University of Montana. Winter conditions that use to kill 80% of beetle larvae now kill only 10%. “It’s game over,” said Running.
Faced with exploding beetle populations and drier mountain conditions, there’s only so much that the Forest Service can do. “We don’t have any tools at our disposal to keep it from happening,” says Furnish. “It’s just racing across the landscape. Humans are just watching it all.”
|Life & death: Gray & green strands tally the casualties|
And where is it racing to, we wonder? Forest Service entomologist Bob Cain says the beetle infestations are moving north and east. A freak wind storm in 2006 blew the beetles eastward from British Columbia into northern Alberta for the first time, where they have set to work on the boreal forests spanning the Canadian northlands. Colorado’s beetles have appeared in Nebraska. And they are acquiring a taste for previously unaffected species, like the jack pine, threatening forests that never developed natural defenses.
So if God’s beautiful symphony brought together the seasons and the snows to balance the needs of trees and beetles, what does our disharmony sound like in the new world of climate change? Here’s an extremely limited sampling:
- Dead and weakened forests in the Southwest are burning at an unprecedented pace. Texas, New Mexico and Arizona have lost millions of acres of forests and thousands of homes this summer to explosive wildfires.
- Many Southwest forests are not recovering, but converting to unproductive heat-tolerant scrub and grasslands due to new, drier climate conditions. These lands cannot begin to hold the amount of carbon – or provide habitat to wildlife – that forests can.
- 80 percent of British Columbia’s massive western lodgepole forests have been devastated by the beetle infestation. And it’s headed eastward across Canada, a country that accounts for one-third of the world’s forested area.
- Beetle-killed forests are tinderboxes, and after 5-10 years, the shallow-rooted trees simply fall over, blocking roads, destroying power lines, and endangering humans.
- Many Rocky Mountain recreational destinations like Steamboat Springs are now surrounded by dead forests. Communities will have to live through the red forest stage, followed by a grey moonscape after the dead needles all fall. And for a decade or more, falling trees will render it unsafe to go into the woods.
|Almost pretty: Red hues disguise the horror of mass mortality in B.C.|
- Falling dead pines disrupt the forest soil structure, giving rise to erosion which chokes streams and reservoirs, and imperils community water supplies.
- The forest die-offs are both the result and the cause of rising greenhouse gas concentrations, as dead or burning forests emit far more CO2 than they absorb. It’s an example of the many positive feedback loops that make climate change so tricky to forecast, and often drive unpleasant, un-forecasted surprises.
|Nice vacation? Dead lodgepole forest up close.|
|Are Alberta’s boreal forests next?|