As far as "boreal forests warm the climate" is concerned, a few references are: [Betts (2000)](http://www.nature.com/nature/journal/v408/n6809/full/408187a0.html), [Bala et al. (2007)](http://www.pnas.org/content/104/16/6550), and [Bonan (2008)](http://www.sciencemag.org/content/320/5882/1444).