I mentioned in my first post that I wanted to do a little more research about fires in the Tundra before providing you with any more insight into their importance up here. The smog from the recent fires has finally cleared the past few days, giving us a gorgeous view of the Brooks Range. However, I realized that although I generally know that fires are common in Alaska and often originate from lightning strikes during the summer months, I don't know much else about tundra fires. When I took classes in ecology way back when, we learned that forest fires were important to allow proper forest sucession. Some plants have seeds that may only be germinated once exposed to fires. In addition, we were told that fires clear out the excess of plant debris build-up. They sort of 'wipe the slate clean' in the forest. Before looking into the fires, I assumed they played a similar role in the Arctic and are necessary for succession of the landscape. However, after doing a bit of reading I learned that there are a few big differences between forest fires and tundra fires and much greater concern about the recent tundra fires in the Arctic.
Before I go into this, I want to say that I am by far not an expert in this matter, but just found some of these facts interesting and wanted to pass them (and a few articles) along. One of the interesting facts that I found about Arctic tundra fires is that we are still learning about the importance and function of fires in the Arctic ecosystems -- most information on this topic was published in the last 5 or 10 years. Alaska experienced the largest and longest burning fire on record during 2007, which occurred near the Anaktuvuk River, a short helicopter ride from the Toolik Field Station. At Toolik this site is just referred to as "the burn site." Scientists here have a unique opportunity to study the effects of fire on many aspects of the Arctic ecosystem as well as examine how quickly the environment may recover. Much of our understanding of how the Arctic responds to large-scale fires originates from research of the 2007 burn site.
Tundra fires are a topic of current of concern since as the climate in the Arctic becomes warmer, the frequency of scale fires has increased. Recent research has revealed several basic reasons why this is an issue. The first reason is because the fires release massive amounts of stored carbon to the atmosphere in the form of carbon dioxide (which is a greenhouse gas). The tundra stores large amounts of carbon in the plants and and organic materials. However, the fires result in a rapidly release of the sequestered CO2 back to the atmosphere. The excess carbon release is not limited to the period of burning -- the effects of reduced vegetation and elevated microbial degradation of freshly released organic material results in a large excess of flux of carbon into the atmosphere continues once the fires subsided.
The second reason that tundra fires are of concern is the effects on the permafrost. Similar to forest fires the tundra fires reduces the reserve of organic material (dead plants etc.). The difference is that the presence of this organic layer in the Arctic tundra is necessary as insulation to the underlying permafrost. Thus the lack of this insulation results in more rapid melting of the permafrost which may have many consequences (e.g. increased microbial metabolism, increased CO2 production, destabilization of land surfaces ...). With increased frequency of fires, the vegetation in the tundra does not have adequate time to recover and rebuild the organic layer, resulting in devastating losses to the permafrost.
If you're interested in more detailed explanation about the burn, here are a couple of nature articles about the effects of the 2007 fires in Alaska: