Assignment Earth: Whitebark pine beetle
A tiny beetle threatens the existence of Whitebark pine forests.
Gary Strieker takes Assignment Earth to a higher altitude, where the tiny mountain pine beetle is wiping out once mighty Whitebark pine forests in northwest Canada and the U.S. Warmer temperatures have allowed the beetle to thrive at altitudes where it previously could not survive. University researchers and forestry experts are racing to create a disease-resistant strain that can withstand the beetle assault, but time is running out for the forests and the many animals they sustain. (Video: Assignment Earth)
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[MUSIC]
>> It’s already dead. It’s a goner.
>> Living at tree line, the white bark pine thrives in one of nature’s harshest environments. But these mighty trees, some more than 1,000 years old, are no match for this tiny beetle.
>> Essentially, all day long, I have not seen a tree larger than about six inches around that’s not being killed by a mountain pine beetle.
>> A native pest, the mountain pine beetles typically target lower elevation forests.
>> While you see a lot of death and destruction, this is actually a very normal pattern when you're looking at lodgepole pine at least.
>> But the epidemic is new white bark pine. In the past, freezing temperatures kept the beetles out of the white bark’s high altitude domain. But scientists say warmer winters due to climate change are allowing these beetles to thrive at higher and higher elevations.
>> -that the tree produces against the beetle, so when -
>> Lodgepole pines have evolved to combat beetle attacks. They produce resin to ward off these tiny invaders, but white barks don't appear to be as well prepared.
>> These trees really appear to have almost no defenses against the insect.
>> Beetles aren’t the only problem. White pine blister rust, a fungus introduced from Europe, is also killing white barks. Scientists are racing to find genetically resistant specimens. The plan is to collect their seeds and eventually replant a disease resistant forest, but now the beetles are threatening to wipe out even those disease resistant trees. Losing these forests could impact the birds, squirrels and grizzly bears that feed on white bark pine seeds.
>> We’re walking through this forest, it’s alive in Clark’s nutcrackers and squirrels. We’re seeing bear scats with whitebark pine seeds.
>> In the Greater Yellowstone area, red squirrels cut cones out of trees and store them in minutes, which grizzlies raid. Female grizzlies depend on the high fat seeds to sustain their pregnancies.
>> It’s as close to a free lunch that there is in nature.
>> But with warming temperatures, beetles have already attacked most of the whitebarks in this forest.
>> It’s a pretty good cone crop this year, but this is the last crop.
>> For Assignment Earth, I’m Gary Strieker.
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