The fire suppression
policies enacted by the United States are having extremely detrimental effects on most wildland areas of the US. One of the most severely damaged areas is the forests in the northern Sierras
near Lake Tahoe
. In the case of this forest, extreme actions must be taken soon or a stand-replacement crown fire will probably destroy the whole forest. If this happens, the lake
waters, famous for their clarity, will also be darkened for decades.
The forest above Lake Tahoe is a mixed-conifer forest, made up of many trees, such as Ponderosa Pine and White Fir. The area experiences lots of lightning in the summer and thus historically has had frequent fires. In the times before active fire supression, the forest was very open, allowing a wide diversity of smaller plants to survive. The forest was also more suitable for deer and other wildlife. Ponderosa Pines dominated the landscape, with many other species present as well.
The forest today is literally cast under the shadow of looming disaster. Without fire, Ponderosa Pine is not able to compete effectively with other trees. Shade tolerant trees like white fir have taken over the understory and are fast becoming the dominant tree. Unlike Ponderosa Pine, White Fir is extremely flammable and subject to violent crown fires.
To 'add fuel to the fire', these firs are growing very close together. When trees grow too close together, they are vurnerable to boring beetles and other pathogens. And the trees are dying. In some places, over half the trees are dead! And the only thing that burns better than a living white fir is a dead white fir. (think torching a dried out christmas tree, a million times over). Basically, the forests now are tinder dry. Under the right conditions, the whole forest is likely to go up in smoke. In addition, there will be no way of protecting the cabins scattered between the trees. After the fire moves through, the lake will become clouded with sediment.
Is there something we can do? Yes, but it won't be easy. The forest is so dry, that starting a prescribed burn would be a disaster (aka Los Alamos). To fix our damage, we will have to go in and manually thin the trees, before initiating prescribed burns. Will it get done? Probably not.. but if it doesnt happen in the next 10 years or so, Nature will remove the trees for us, along with all human structures in the area.
For more information on fire supression and its ill affects, see Why fire supression doesn't work - Case study: Chaparral and Why smokey bear was wrong