Yet another reason to cherish North America’s great boreal forest comes in a new report saying that the forest plays a critical role in curbing climate change.

I always have valued this vast forest -- which touches northern Minnesota and fans broadly through Canada -- because it is a seasonal home and breeding ground for so many of the birds we see migrating south right now.

It turns out that the boreal forests also are one of the world’s most important carbon banks, storing 22 percent of all carbon on the earth’s land surface. The report, “The Carbon the World Forgot,” says North America’s boreal forest stores the equivalent of 26 years of global emissions from burning fossil fuels, based on 2006 emissions levels.

Some of the boreal carbon has been in place for up to 8,000 years, stored in trees, permafrost and peatlands where organic matter has accumulated over millennia.

One dreaded scenario for global warming’s impact on Minnesota is that the trees defining the boreal forest - including balsam fir, spruce and paper birch - will decline as temperatures rise. This new report raises prospects for a destructive cycle in which the decline of the boreal causes considerably more carbon to be released.

Much of the international effort to protect forests in order minimize climate change has focused on the tropics. This study’s authors call for looking as well to the boreal forest as international climate negotiators meet in Copenhagen next month. The consortium releasing the study included the Canadian Boreal Initiative and the Pew Environment Group’s International Boreal Conservation Campaign.