NASA satellite image of Mountain Pine Beetle damage. {Larger, interactive version available here}
Don't get me wrong, my kids and i have watched, loved and learned from Suzuki's Nature of Things for decades. This episode though comes off as a bit lopsided in that it so obviously is focused on only one of the many factors at work in the MPB's recent population explosion - climate change.
Although climate change is a big factor in the MPB epidemic other factors both human and natural play at least as big of a role. In the show an entomologist mentions fire suppression saying, "There is currently an over abundance of mature lodgepole pine, which is the host tree for the mountain pine beetle, creating an unnatural manmade situation. This is driven by social policy, and maintained by society's view that fires need to be put out." The cold-blooded MPB has a genetic resistance to cold temperatures, but clearly not to fire. Fires also naturally remove the host species, creating a mosaic of age classes and tree types.
Fire suppression is done to protect homes and lives but it's also done to protect the financial value of the timber. In addition there are other financial reasons beyond fire suppression why our interior forests contain an over abundance of similarly aged mature trees that the doc. doesn't mention including the massive clear cutting that has dominated our forests since the colonial capitalists took over. In the early days those clear cuts were naturally re-seeded, which at least created a partially mixed forest. In the last few decades they have been replanted mostly as lodgepole pine mono-cultures - tree farms. In both cases though the rssults are trees of a uniform age, a perfect habitat for all kinds of natural levelers - including the Mountain Pine Beetle
Normally, these insects play an important role in the life of a forest, attacking old or weakened trees, and speeding development of a younger forest. Unfortunately the short-sighted human 'profit' myopia has resulted what may be the largest forest insect blight ever seen in North America. The show beautifully shows that the MPB is now munching it's way into the Boreal forest in Alberta and is headed across the continent compromising both one of the world's great oxygen producers and it's capacity to sequester greenhouse gases as it goes.
BC's panic driven response in the last two decades has been to turn loose the lumber industry allowing it to mow down everything in sight in every huger clear cuts which of course will end up regrowing an over abundance of similarly aged trees. Apparently BC's leaders haven't learned that a 'forest' is an interwoven, integrated, interdependent ecosystem, that real forests have a great diversity of trees and other species that work together to keep themselves in balance. The Mountain Pine Beetle isn't an ecological disaster it's part of Mother Nature's immune system which is working to rid itself of the rogue primate who's technologies are the ecological disaster.
