USA — Jim Pitts stood on a Forest Service road near the Arizona town of Nutrioso and surveyed the damage in the valley below. It was July, and only a few weeks earlier the Wallow Fire, the largest in recorded history in Arizona, had swept through this section of steep slopes and tightly packed trees.
This is pretty devastating, both from the forest standpoint and the human aspect, said Mr. Pitts, a Forest Service silviculturist. Its going to take a long time to get this forest back to the way it was. It wont happen in my lifetime when its got to start over.
Temperatures in the fire could have been as high as 2,000 degrees Fahrenheit, Mr. Pitts figured. Heat like that cooks trees to death from across roads. Nearly a half-million acres of forest burned in the Wallow Fire, which followed another huge and destructive wildfire, the Rodeo-Chediski in 2002.
Certainly, over the last decade, were seeing more large fires more frequently, said Christopher M. Knopp, the forest supervisor of the Apache-Sitgreaves National Forest.
I conveyed the magnitude and import of these huge Southwestern forest fires in a video report posted at the Times Web site this weekend. Focusing on Arizona, it was produced to accompany a major article by my colleague Justin Gillis, who reported from Montana about what seems to be a rising trend of forest die-backs around the world.
The article talked about HUGE fires and beetle kills that, aside from their local effects, raise questions about the ability of the worlds forests to keep taking up the carbon dioxide that humans are emitting. Mr. Gillis found that climate change poses a risk to forests, particularly in the already dry climate of the American Southwest.
In Arizona, the most interesting thing I found was that big, destructive fires have caused many groups to seek common ground in reversing the trend. A coalition of land managers, scientists, environmentalists and loggers have come together to combat the fires, making strange bedfellows of groups that fought each other during the timber wars of the 1990s.
The emerging consensus is that the Ponderosa pine forests of northern Arizona and New Mexico have been mismanaged for more than a century. Small ground fires historically burned through these forests with some regularity, keeping the trees widely spaced. But decades of fire suppression have allowed trees to grow so thick that the forests are now referred to as dog-hair thickets.
The small fires of old would generally leave large Ponderosa pines intact; the trees have a spongy bark that resists ground fires. But in an overgrown forest, flames can climb the small trees into the high forest canopy, creating a crown fire that can leap with the winds and take out thousands of acres quickly. While crown fires can play an important ecological role in other types of forests, for Ponderosa forests they can be highly destructive and a liability to the forests ability to capture and store carbon.
Massive fires like the Wallow and the Rodeo-Chediski not only pour carbon back into the atmosphere; if areas are burned badly enough, the forest can be permanently destroyed. Ongoing climate change makes that more likely, favoring heat-tolerant grasses and shrubs over trees. I visited areas burned in the Rodeo-Chediski fire that are not recovering as forest a decade later, and Mr. Gillis saw the same thing in Montana.
Many now believe the solution, across much of the West, is to cut down the spindly dog-hair trees and restore forests to something akin to historic density levels, at times reducing the tree cover from as many as 800 an acre to fewer than 100.
The White Mountain Stewardship Project, created after the Rodeo-Chediski fire, serves as an example of a way that various stakeholders have been able to nurse some forest areas back to health. In our video, Dwayne Walker, a fourth-generation timber man, speaks of the return of logging and jobs in some of the poorest parts of Arizona.
Mr. Walker and his business partner Rob Davis run a company called Future Forest; they won the White Mountain Stewardship contract to thin 150,000 acres over a 10-year period.
Mr. Davis, who runs a wood pellet manufacturing facility in Show Low, Ariz., has helped to build an economically viable way to put some of the smaller trees clogging the Southwests forests to use. Many in nearby communities credit the thinning and the hard work of fire crews with saving their homes and businesses.
Mr. Davis argues that better management preserves forests and their ability to clean the air, filter water and store carbon dioxide. I dont think the country gets how much benefit we get from having healthy, sound, sustainable forests, he said.
Many experts say treating forests pre-emptively could be more cost-effective than fighting huge forest fires. Yet, in tight budget times, the United States Forest Service does not have nearly enough money to do the work. Still, a new program called the Four Forests Restoration Initiative is taking shape and aims to thin more acres.
The big limitation on all of this, when were talking about treating the forest, is economics, said Mr. Knopp, the Forest Service supervisor. The Wallow Fire points out that the quantity of material that weve been able to treat, even though it was strategic and was logical, it wasnt enough.