Climate change is threatening US forests right now.
Threats from Global Warming
Global warming will have a huge impact on western forests, and in fact already is. Warmer winter temperatures are contributing to unnaturally large, frequent and deadly outbreaks of bark beetles. As a result, nearly half of Colorado's 660,000 acres of lodge pole pine forests were infested by mountain pine beetles in 2006. Eastern Washington State lost 4million ponderosa and lodge pole pine trees in 2004 alone. Outbreaks have also occurred in Alaska, Arizona, California, Idaho, Montana, New Mexico, Oregon and Wyoming.
These tree-killing insect epidemics set the stage for catastrophic wildfires, especially in combination with the higher temperatures caused by global warming, leading to lower soil moisture. Moderate fire is natural and helpful in many ecosystems, but catastrophic, drought-fueled fire with abundant fuel from large acreages of dead trees can destroy vast expanses of wildlife habitat, put human lives at risk and cause extensive property damage. In the Western United States scientists have documented a six-fold increase in the area burned over the past two decades, which they attribute to global warming. These forest fires exacerbate the global warming problem because the burning forest releases more carbon dioxide into the atmosphere.
The economic costs of tree die-offs and catastrophic fires associated with global warming are almost beyond reckoning. Damage to homes and property from wildfires totaled $3.2 billion during the 1990s. In 2006 alone, the Federal government spent $1.5 billion to fight forest fires (throughout the U.S.). While loggers have in some places turned to harvested trees killed by insect epidemics, large forest fires lead to the loss of income and jobs in the logging industry. Continued warming and more severe droughts associated with global warming will only further increase the risks and costs of catastrophic wildfires.
Catastrophic fires are especially damaging when they destroy the fertile detritus layer of soils, leaving only highly erodible mineral soils. Reduced vegetative cover, increased erosion and higher stream temperatures are harmful to cold-water species such as trout.
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