Clothesline in Winter

Clothesline in Winter

Thursday, October 20, 2011

What's Killing the Rocky Mountain Forests?

God saw all that he had made, and it was very good…..

… And that includes a tiny little creature named Dendroctunus, which in Latin means “tree killer.” We know Dendroctunus as the Mountain Pine Beetle.  It’s been around for millions of years.  And its favorite meal is the lodgepole pine – and other pines, like ponderosa and whitebark pines.

God’s pines are also very good.  He endowed them with nifty defenses against the pine beetle.  They emit a waxy white resin into the beetles’ drill holes to drown the invaders.  So if there’s enough moisture, and not too many beetles, the pines can usually recover to serve their Maker for many decades.

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.

Even fire plays its part in God's beautiful Rocky Mountain symphony.  Forest fires clear out excess vegetation and dying trees, and cause the lodgepole pine cones to open and release their seeds, giving rise to a new generation of vigorous young trees.

Fire and ice, winter snow and summer stream, massive tree and tiny beetle – all working together in harmony balanced by the laws of nature, responding to the good hand of their Creator.  Every so often, beetle infestations would break out with notable damage; but the forests generally recover with the help of the cold winters and steady summer snow melt.

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.

Veteran forester Jim Furnish has been watching the trees and beetles for almost four decades. In his 34 years with the U.S. Forest Service, Furnish saw “bug epidemics” come and go.  “But what’s shocking is that no one’s ever seen anything like this,” says Furnish. “The scale is something no one’s ever contemplated before, from Alberta to Northern New Mexico.”

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.

At the same time, formerly cool spring and summer weather in the Rockies used to provide an extended snow melt, maintaining the health of the forest throughout the warm seasons.  But with longer and hotter summers, the pines are coming under severe water stress.  Healthy trees drown the beetles in resin; without water, the weakened trees are an easy meal for the beetles.

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.
Those of us who regularly warn about the perils of climate change often speak of risks to our children, or to far-off peoples.  But Jim Furnish reminds us that this is now, and it’s here:

“This is different.  You can’t deny that it’s happening.  But some will always blame the Forest Service or insist that mankind is not to blame.”

Maybe, Jim. But just maybe, this catastrophe will awaken some Americans.  Maybe we'll demand climate action from our leaders to stop the misuse of God’s good creation. Let's pray that it will.

Thanks for reading, and may God bless you. 

J. Elwood

How bad?  The red-orange areas are recent forest die-offs. 

Are Alberta's boreal forests next?

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