How Smokey Bear creates forest fires

By now, many of you are probably aware that human behavior is one of the key factors behind some of the massive forest fires we've seen in recent years. The basic story goes like this: Under a natural cycle, periodic small fires sweep through forests, burning through small trees and dry brush. But if you prevent those fires from happening—as humans have done for around a century at this point—all that highly flammable stuff builds up. In the end, you're left with a giant tinderbox of a forest. The next time a fire does happen there, it's almost guaranteed to be much, much bigger and more destructive than the natural fires that forest is adapted to.

NPR has a very nice story about the science and history behind this problem, which forest fire experts call "The Smokey Bear Effect", after the cartoon Ursus the U.S. Forest Service has long used as part of its fire prevention campaign.

Its ill-advised fire prevention campaign.

And it was the experts who approved the all-out ban on fires in the Southwest. They got it wrong. That's the view of fire historian Stephen Pyne.

"The irony here is that the argument for setting these areas aside as national forests and parks was, to a large extent, to protect them from fire," Pyne says. "Instead, over time they became the major habitat for free-burning fire."

So instead of a few dozen trees per acre, the Southwestern mountains of New Mexico, Arizona, Colorado and Utah are now choked with trees of all sizes, and grass and shrubs. Essentially, it's fuel.

Over the past several years, even as fewer fires have struck the Southwest, they've burned more land. The U.S. Forest Service now spends about half its budget on firefighting.

It's worth noting that this is also a great example of why it's difficult to attribute specific events to global climate change. Increasingly hot, dry summers have certainly been a factor in creating the forest fires we've seen over the last few years. The last decade has been the hottest on record, and that has consequences. But it's not the only thing going on here. Climate change doesn't happen in a vacuum. Its effects interact with the effects of other decisions we make (and other natural events that happen to be taking place). So it's not enough to say what climate change will do. In order to make accurate predictions of risk, we have to think about the bigger picture and how climate change fits into it.

Read (or listen to) the rest of the story at NPR's website

Via Finn Ryan

Image: Forest Fire, a Creative Commons Attribution (2.0) image from wandrus's photostream

Dispatches from Harvard Forest

I’m currently attending the Marine Biological Laboratory’s 10-day science journalism fellowship. As part of that, I get to do some hands-on science experiments and get a better perspective on how the work of science is done and how data is collected.

Read the rest

Robots could help manage forests

Jared Keller on the new science of forestry robotics: "The vast majority of forests are destroyed by wild forest fires, and current methods of sylvan vigilance -- mainly those involved individual personnel on foot patrol -- are grossly inefficient in identifying emerging threats. Rob

How the effects of climate change can create more climate change

One of the interesting things about the global carbon dioxide and climate systems is the concept of feedback loops. You already know that as atmospheric concentrations of carbon dioxide go up (and with them, the global average temperature) you get lots of different kinds of changes all over the place. For instance, mountain pine forests start experiencing warmer winters and smaller snowpacks. But, as those changes happen, they can actually trigger secondary effects that contribute to, and increase the rate of, climate change.

In this video, you'll learn about how warmer temperatures and lower snowpacks are contributing to the spread of massive pine beetle infestations across the western United States. This is more than just inconvenient. The pine beetles can quickly kill huge amounts of trees, raising the risk of property-destroying forest fires and razing whole ecosystems. And, as the trees die en masse, forests that were once carbon sinks (absorbing more carbon dioxide than they released) become emitters—adding more carbon dioxide to the atmosphere.

Thanks to Barfman for Submitterating!

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