Pax

.... is a complete bastard if you happen to be a lodgepole pine or one of its close relatives.
Rising global temperatures occuring in the last twenty years has meant that this particular species of bark beetle (Dendroctonus ponderosae), has been abnormally surviving winters in large numbers.

The beetle burrows into the innermost layer of the bark, the phloem, often in large numbers. The tree responds to this damage with heightened levels of resin production. However, the beetle carries a fungus that helps to block this resin production, ultimately leading to the death of the tree. A mortally wounded tree will take on a reddish hue for a period before finally dying and turning a grey colour.

In western Canada and the northwestern United States beetle infestation has reached epidemic proportions and very large numbers of lodgepole and other pine have been seriously affected, with models predicting up to 70% mortaility of current mature trees. So far this problem has been confined to west of the Rocky Mountains, but there are now signs that it is spreading eastward.