Pine Beetle Evidence

Northern British Columbia is marvellous. Remote, not very many people at all and relatively undeveloped. This scene here, however, depicts a very worrying phenomenon. It may look nice enough, but that nice red colour spells disaster. What you see is how British Columbia is losing many of its trees. Logging is definitely an important reason, but what is going on right here will have a much larger impact.

All the red trees that you see here are dead. They have been killed by a tiny beetle called the Mountain Pine Beetle, which lay their eggs in the trees in such large numbers that the tree cannot survive. The beetle has been part of the natural system here for a long time, but until quite recently cold winters kept their numbers in check so that they limited themselves usually only to weak trees. With winters becoming a lot warmer in the past few years, beetle numbers increased explosively and even strong trees succumbed.

But apart from dramatically speeding up climate change, humanity has farther guilt in this big problem. Our ways of controlling forest fires, for example, has contributed significantly to make it easy for the beetles. When natural fires still occured, a fores consisted of patches that were in different stages of recovering from fires. This meant that you would find a patch here that had mostly just saplings or even just weeds because it was burned recently. The next patch would have some taller trees, but these would still be young, juicy and green. And then there would be places where the trees were old and where much dead material would have accumulated on the forest floor. These last patches, of course, would be particularly vulnerable to burning if the conditions were right. In this way, forest fires were extremely useful. In fact, the forest depended on it for its survival. The suppression of fires has dramatically changed some forests. Instead of patches in different stages of succession, you will find that they are much more uniform. That means that if conditions are right for the beetles, they will be right in a great many trees and not just in a few patches here and there. Naturally this means that their numbers can grow even faster and that spreading out is easier too.

The trees that are still red now in this photograph, will soon go grey when their dried needles fall off. The beetles will continue to work on the remaining trees and spread out to new areas. Eventually all killed trees will fall and leave a devastated place. This natural system is very poorly equipped to deal with such enormous changes and at this time it is very unclear how hard the beetle's strike will be. A cold spell in early 2008 might have killed off many beetles, but this is not certain yet. But even if that would be true, it is ever more likely that future winters will be warmer and warmer. Worst case scenario is that pines in North America will virtually disappear. Moreover, there is a very similar thing going on with spruce trees and spruce beetles. Nobody can really foretell what will happen if forests will change as dramatically as seems possible these days...

Image number: 2007_ASP5035LCA