Forest management: Difference engine: Fire on the mountain | The Economist
- IT CAN even be seen from space and smelt 240 miles (390km) downwind on the ground. The wildfire raging in New Mexicoâ€™s historic Gila National Forest has already scorched some 230,000 acres (93,000 hectares) of woodland, making it the biggest in the stateâ€™s history, and the largest by far of the two dozen uncontained blazes that firefighters are currently battling across the country. The good news is that, as the fire season in the American west gets under way in earnest, the tally of burned acreage to date is running 40% below last yearâ€™s rateâ€”despite the regionâ€™s relatively dry winter.In many ways, the New Mexico blaze is a test case. It represents the first large-scale opportunity that firefighters have had to test a new approach to forest management. This relies on pruning the undergrowth and thinning out the stands, and then letting nature take its course when lightning strikes and triggers a blaze.That is not to say firefighters in New Mexico have stood idly by. They have doused flames, removed fuel in the fireâ€™s path and carved containment lines around parts of the wildfireâ€™s perimeter where communities could be threatened. Other than that, the object has been to steer the blaze so it can do its job safely and effectively. As planned, the fire is burning more slowly and less ferociously than might otherwise have been the case. Vindication, then, for the Forest Serviceâ€™s new policy of reducing the fuel-load on mountain sides on a regular basis using chainsaws and prescribed burns.The restoration work the Forest Service has undertaken of late in places like Gila has had other benefits. Thinning and clearing out the â€śtrash treesâ€ť not only influences how quickly and intensely wildfires burn, but also reduces the amount of soil erosion and the impact loosened debris has on the watershed. In turn, that makes forests more resilient to torrential downpours, epidemics of insect-borne diseases and even climate change.Actually, there is nothing new about the latest approach to forest management. Native Americans were practising similar forms of forestry long before settlers arrived from Europe. Where lightning had not done the job for them, they set fires to thin the forestsâ€”so grasslands and edible plants could flourish between the trees and attract grazing animals for hunting. Records indicate the land in pre-settlement times had no more than a dozen trees per acre. Todayâ€™s forests, whether natural or man-made, tend to be packed with well over 100 trees per acre.
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