From the US Geological Survey:

Tree death rates have more than doubled over the last few decades in old-growth forests of the western United States, and the most probable cause of the worrisome trend is regional warming, according to a U.S. Geological Survey-led (USGS) study published in Science on January 23.

The study found that the increase in dying trees has been pervasive. Tree death rates have increased across a wide variety of forest types, at all elevations, in trees of all sizes, and in pines, firs, hemlocks, and other kinds of trees.

Regardless of the cause, higher tree death rates ultimately could lead to substantial changes in western forests, said Phil van Mantgem, a USGS scientist and co-leader of the research team.  Such changes, the team noted, can have cascading effects, such as by changing forest suitability for wildlife species. Additionally, increasing tree mortality rates mean that western forests could become net sources of carbon dioxide to the atmosphere, further speeding up the pace of global warming.

1. 
   Roger 2009 01 23 at 1:36:52 am

   Not a whole lot we can do about natural cycles in sunspots and the earth’s climate.

2. 
   Chris Clarke 2009 01 23 at 1:10:32 pm

   Or non-sequiturs! Non-sequiturs are probably inevitable too.