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English > Historical Fires > 2000 Fire Season > Effects of 2000 > Effects on the Forest Ecosystem
Many things were positively and negatively affected in the forest ecosystem as a result of the fires.
The topics covered are split into soil, fish, wildlife, trees and shrubs, and noxious weeds.
- Soil
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Flooding and Mudslides:
Large problems can occur in places that have been seriously burned, because the vegetation and trees that hold the soil in place are dead or weakened, and the soil moves easily. It also is cemented together (as described in the composition and structure section, below), so that water can’t penetrate the soil, and just sits on the top. If a large amount of snow falls, or if there are large rainstorms in the spring/summer, massive landslides can occur.
One of the many mudslides in Laird Creek, that happened in 2001.
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Places like Laird Creek, in the Bitterroot Valley, Montana, experienced massive mudslides, because the whole valley was completely torched. There was a large rainstorm in the spring that dumped 1/2 inch of rain in 30 minutes- many houses that had just been rebuilt from last year’s fires were flooded, and the whole road to Laird Creek had to be rebuilt. During the flood, many of the small side canyons collapsed, and sent soil into the canyon. The small Laird Creek, which is normally about 2 feet deep, reached 8 feet right after the rainstorm.
While talking with Craig Thomas after the interview, he said that he had flown over much of the burnt forest in the wilderness, and the mudslides were up to a couple of miles long- nothing compared to what you could see by car.
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Composition and Structure:
When fires burn very hot, as many did in the fires of 2000, the fires not only destroy all the vegetation, but they destroy any organic matter, including fungi that aid in plant productivity- in essence, the soil becomes sterile.
During the fires, a byproduct of the burning vegetative matter is hydrocarbons, which essentially cement all the soil particles together, creating a soil that can’t absorb any water. This makes it very susceptible to flooding and as a result, mudslides.
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Erosion:
The steep terrain that has been badly burned is easily eroded, and not only can this create short-term problems, like mudslides, but the topsoil can wash away. If the topsoil washes away, it is very hard for plants to grow in the area.
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Fish
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Fisheries/Fish Population Damage:
Many of the streams (126 of the named fish-bearing streams in the Bitterroot National Forest burned) experienced severe fire damage. Thousands of fish kills occurred on many of the streams as a result of the fires, mostly in the severely burnt drainages. Previous studies have indicated that it can take up to three to five years for the full population to recover. In some of more severely burned drainages, like those in the Bitterroot Valley, Montana, are supposed to recover within 10 years.
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Landslides/Vegetative Loss:
Although landslides are initially harmful to fisheries, they actually contribute the fish’s habitat, and benefit the fish. The loss of vegetation on some high-elevation streams could actually provoke the fish population growth, because it warms the streams some.
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Wildlife
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Snags:
There are many snags that now exist as a result of the fires, which provide the habitat required by some birds, such as some species of woodpeckers, who need snags to nest in, and other animals that use holes created by woodpeckers as their home.
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Lynx:
Lynx need a young, dense forest, to hunt for snowshoe hares that live primarily in that environment, and make up a large percentage of the lynx’s prey. So, as the forests rebuild, it will create a perfect habitat for the Lynx
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Old Growth Forest Destroyed:
Much of the forest that was burned, was old growth forest, and was prime habitat for owls, pileated woodpeckers, and other animals, that need the woody debris, and old trees to provide an optimal habitat for them. Also, much needed shade was destroyed, which elk greatly depend on. The reduction in tree canopy also creates an environment that harbors the growth of noxious weeds (discussed in more detail under the Noxious Weeds section, below).
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Reduced Wildlife Habitat:
The reduction of overgrown forests creates easier access for motorized vehicles in many places, therefore affecting the wildlife habitat that lives in those areas that the vehicles can now drive in.
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Trees and Shrubs
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Suppression and the Growth of Forests:
The suppression of fire that occurred in the 20th century wasn’t the cause of all of the fires of 2000, but it was the cause of the more severe fires. Normally, fires will go through with low intensity every 5-25 years, and clear out some of the underbrush, and some of the trees. An optimal forest would be somewhat open, and would have many trees of different ages. Unfortunately, the fires suppression created a forest that was filled with fuel, and that could burn almost forever.
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No Diversity:
The forests weren’t very diverse: not only in age, but also in the type of trees. In areas that contained a lot of Douglas fir, were greatly affected by the Douglas fire bark beetle, and many of the Douglas fir were wiped out. The forest had a lot of areas that were just one tree, or another, and most of the trees in a specific area were all the same age. As mentioned above, this isn’t a healthy forest, and often leads to severe wildfires.
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Shrub Regrowth:
As a result of the fires, many of the shrubs and small plants will come back with increased intensity. Also, many of the native plants and shrubs respond well to fire, and will come back in great quantity, creating a more diverse vegetative population.
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Noxious Weeds
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Danger of Infestation:
Although many of the native plants will be able to grow back after the fire, the places that have been severely burned lack any plants that want to grow there, and often weeds will be able to come in and infest these sensitive areas. There isn’t any competition in these areas, letting the weeds possibly take over.
© ThinkQuest Team C0119184 :: Credits & Sources
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