This is nonsense. The major control on pine beetle is food supply. When their food is abundant and available they multiply accordingly. The existance of pine trees is the abundant part, but that isn't enough in itself, there also has to be a considerable amount of weak trees in order to get populations up to critical mass in order to get the kind of infestation we're currently experiencing. The older the trees, the more vulnerable. That's the available part. 100 years ago we only had 1/4 the number of mature pine trees as now. We've been fighting them off for 40 years with declining success as outbreaks became more and more frequent as the years progressed and the trees became weaker. When the current outbreak started in Tweedsmuir Park, the (environmentalist supported) NDP governemnt refused to let any action be taken against them, no matter how much the forest companies, loggers, BC Forest Service pleaded and begged and warned of what could (and did) happen if left unchecked.
If cold was the main control on beetles, then they would have long ago destroyed the pine stands in the southern parts of the province where it never gets that cold. Pine beetles are found wherever pine trees are found, whether in the south or north, and scientists tell us that this has been the case for 60 million years.
I also recall the cold conditions of the winter of 1985-86. The killing cold snap occured in October when temperatures dropped to -36 before the beetles had time to form their anti-freeze and before enough snow had accumulated to insulate them (they retreat to the base of the tree to overwinter). That cold snap killed off the spruce bark beetles that were infesting the forests east of Prince George but the pine beetles emerged relatively unscathed. We were still fighting them off the next year.
