Chopping Down Trees to Save Forests

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. 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... 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 forest’s 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...more