According to a recent study published in the journal Sciencexpress, global warming and not mismanagement of forests is responsible for the accelerating incidence of catastrophic forest fires in the West, reports the Wildlife Management Institute.

Authors of the study are scientists at the Scripps Institution of Oceanography and the University of Arizona. The study was funded by the U.S. Forest Service, National Oceanic and Atmospheric Administration, and the California Energy Commission. A key finding of the study is that the major factor leading to the increased fire risk is increasingly early spring snowmelts, which have extended the annual dry period and the fire season, and have produced drier vegetative conditions overall. The trend of earlier snowmelts is attributed to global warming.

The average number of wildfires reportedly increased by a factor of four in the mid-1980s and burned 6.5 times the acreage burned in the 1970s. The study also showed that annual changes in wildfire frequency were linked closely to annual spring and summer temperatures, with greater fire frequencies occurring in the comparatively hotter years. Fifty-six percent of the fires studied and 72 percent of area burned occurred in early snowmelt years. In contrast, only 11 percent of wildfires occurred in late snowmelt years, and those fires burned only 4 percent of the area.

The study presents information from climate models that predict that warmer springs and summers will continue to intensify, further exacerbating the western wildfire problem. Such will predictably result in increased threats to ecosystems and human communities, and at an annual cost greater than the $1 billion plus in recent years. Already in 2006, according to the National Interagency Fire Center, fires have burned nearly 4 million acres nationwide, with over 2.8 million acres burned in the 11 western states plus Texas and Alaska.

Recent forest management strategies for the West have concentrated on buildup of fuels to fire suppression and reduced logging on national forests. They reflect concerns that led to the 2003 Healthy Forests Restoration Act. This study assessed forest management versus climate variables in terms of the cause of wildfires. It concluded that climate variables are more important, especially in the Rocky Mountains and high-elevation forests.

An interesting sidelight to this scenario is that increases in forest fires will result in increased atmospheric carbon, reduction in tree densities and reduction in capacity of western forests to sequester carbon?all of which will likely contribute to more global warming. (lhc)