According to an article on reuters.com titled Climate change fans deep-burning fires in Alaska by Deborah Zabarenko, climate change in Alaska has caused longer fire seasons and deeper burning fires. The forest fires, which have been caused by lightning and human intervention, have been occurring more often due to the longer summer season caused by the earths' warming. This longer fire season starts to burn not only the ground cover but also the carbon that is stored in the soil as deep down as 26 feet. This emission of stored carbon, which is called peat, has caused Alaska to become a major contributor of carbon emissions into the atmosphere. According to Zabarenko, a forest fire in Alaska in 2004 emitted more than 56.7 million tons of carbon in 90 days. This amount of carbon emissions is astounding since this is more than the U.S. electrical generating plants produced in 90 days.

http://www.reuters.com/article/idUSTRE6B41QS20101205
http://www.alaska-in-pictures.com/forest-fire-in-alaska-3297-pictures.htm