Mountain pine beetles causing wildfires??

October 24th, 2014

Mountain pine beetles get a bad rap for wildfires, study says

By: Kelly April Tyrell

September 29th, 2014

University of Wisconsin- Madison

http://news.wisc.edu/23161 

 

 

Summary:

       Pine beetles are a growing concern in northern forests in the US as they are able to eat their way through thousands upon thousands of longpole pine trees. The beetles cut off the water and nutrient circulation of the tree by eating under the bark called galleries, which quickly kills the tree. Once the tree is dead, its pine needs change to a more redish-brown state and then turn to a shade a lot like gray and then fall to the forest floor. The combination of the dead trunk and all the easily burnable pine needles scattered on the forest floor theorize that trees damaged and killed by these beetles are more prone to wildfires versus healthy trees. However,  UW-Madison zoology professor, Monica Turner and her graduate student, Brian Harvey concluded that in the past few years, even with the rapidly growing beetle population, the beetles barely contributed to the multiple severe wildfires that occurred in 2011- 2013. Professors are growing very concerned on how large the population of beetles is getting to and how the amount of living trees is decreasing. Many professors think that the dead trees contribute to the fire growing, yet the studies that Turner did in Idaho in 2012, demonstrated otherwise. Wildfires are a density independent factor and so according to Turner, the fire will burn whether the trees are dead or alive, but neither one burns faster or quicker or more violently. “No one says beetle-killed forests won’t burn,” says Turner, "but the data set looks at whether they burn with different severity compared to unattacked forests burning under similar conditions. We found that the severity of the outbreak of beetles had almost no effect on fire severity under moderate burning conditions." In conclusion, Turner proved that the beetles killing the trees are not to blame for the severity of wildfires, but they still are causing a serious problem in pine forests.

Connection:

       In our first unit, we discussed the effects of density dependent and independent factors. Both of those are discussed in the article I found. Firstly, the density of forest does not depend on the fire spreading and how long it lasts for. However, with a growing beetle population decreasing the amount of living trees, the density of forests does decrease, yet the fire will still burn rapidly. We also discussed how two different species with some sort of predator-prey or symbiotic relationship can effect each other. Like the wolf and moose population, as the beetle population increases, the healthy living population of longpole pine trees decreases. However, unlike the wolf and moose population which will drop and rise and continue in a cycle, the beetle population will only continue to grow unless some other factor like a disease kills them. The issue is that the size and amount of trees compared to the beetle is quite immense, so the food supply will not run out for a very long time. Finally, we also discussed certain symbiotic relationships, which in this case, I would classify as a parasitistic relationship because the beetle burrows into the tree for shelter and food and in the process cut off the tree's water and nutrient circulation system, therefore killing the tree.