The popular belief that a century of wildfire suppression caused a build-up of fuels in western forests that increased fire risks led Congress to pass the Healthy Forests Restoration Act in 2003. This expensive program gives the Forest Service and USDI agencies hundreds of millions of dollars to reduce fuels.

Now a new study published by Science magazine finds that fuels were not the cause of recent large wildfires. Instead, it was changes in the weather, namely longer drier summers since the mid 1980s.

While some say that the study demonstrates some of the potential effects of global warming, the authors admit that they offer no evidence that global climate change is the cause of the changes in weather patterns (which in fact are a repetition of weather patterns in the 1930s). The real significance of the study is that it demonstrates that the Healthy Forests Restoration Act is a waste of money.

The researchers compared wildfire data with climate data since 1970 and found that "large wildfire activity increased suddenly and dramatically in the mid-1980s, with higher large-wildfire frequency, longer wildfire durations, and longer wildfire seasons. The greatest increases ocurred in mid-elevation, Northern Rockies forests, where land-use histories have relatively little effect on fire risks, and are strongly associated with increased spring and summer temperatures and an earlier spring snowmelt."

These results are not surprising to me. In 2003, I compared acres-burned data with drought data going back to 1931. I found a very strong correlation between acres burned and drought going back to 1953. (The correlation before 1953 was probably lower due to more primitive fire control methods.) I concluded that drought alone was sufficient to explain variations in wildfires in recent years. This led me to oppose the Healthy Forests Restoration Act.

As the authors of this new study point out, only certain forest types are susceptible to higher risk of fires due to fire suppression. These types make up about 85 percent of southern forests, which is why prescribed burning is so popular in the South. But they only make up about 38 percent of western forests, so any money spent "restoring" other forest types is a waste.