Scott Ferrenberg and Jeffry Mitton in the Department of Ecology and Evolutionary Biology at UC Boulder published an article in the October 2013 issue of Natural History on this subject titled “Distressed Woods”. It offers a very sobering description of how climate change is impacting the interaction of the Rocky Mountain forests and the mountain pine beetle life cycle, complete with ugly feedback loops.
While epidemics of beetle attacks have occurred for millions of years, they say “a recent epidemic of mountain pine beetles has raged across the west, killing fifty times more trees each year during its peak than all the wildfires combines … It has left well over a billion dead trees…”
Their studies indicate that the warmer temperatures have enabled the beetles to produce two generations per year instead of the single annual cycle of the past. Further, the ability of trees to fight off the beetle is hindered by the lack of water also linked to our changing climate. To make matters worse, the warmer temperatures enlarge the range of the beetle attacks by allowing it to spread to higher elevations and farther north.
Then the feedback kicks in. The dead trees provide less shade, causing the snow to melt much more quickly and makes the drought impact much worse for those communities dependent on runoff. More worrisome is the fact that our forests that are usually a carbon sink are quickly becoming a huge source of carbon as the vast stands of trees decay or burn.
Listen to an interview on Colorado Matters.
See more detailed publications at Scott’s website.