Difference engine: Fire on the mountain
Thanks to Hipnology for this piece in the Economist
Here’s a quote:
As Ms. Poulos and Mr Workman note, a century’s accumulation of dry fuel on public lands makes it too expensive and risky—for people, property, habitats and carbon emissions—to unleash prescribed fires on a scale needed to manage America’s national forests more efficiently. (Including private land, national parks and other government property, forests cover nearly 750m acres in America—a third of the country’s land surface.) On the other hand, letting the lumber companies loose to go logging in the national forests on such a scale would engender a massive public outcry. So, what is to be done to release the water that over-stocked forests squander?
One practical solution, known as “forest to faucet”, is being undertaken in Colorado by Denver Water, a utility serving 1.3m Denver residents. After severe wildfires stripped the local landscape and left the soil exposed, subsequent storms drove so much sediment down the hillsides that the utility is now having to spend $30m to dredge the streams and reservoirs that supply its water.
The lesson the utility has learned is that, even though it is not its responsibility, it is far better to pay to have the upstream forests thinned and cleared—so future wildfires in the watershed are nowhere near as fierce, river flows improve, storms do less damage and droughts become less frequent. Under a five-year agreement, the Forest Service will share the cost with the utility to ensure the watershed is properly managed. Denver Water’s enlightened customers will each stump up $27 over the period.
This public-private approach is the kind the Wesleyan researchers favour. They note that water rights in western parts of America are valued at $450 to $650 per acre-foot and rising. It therefore pays thirsty downstream communities to spend $1,000 per acre (the average cost to the Forest Service) to remove the fire-prone trash trees in upstream forests that affect their water supply. In return for their investment, they get the 2.3 acre-feet of water (worth $1,000 to $1,500), which would have otherwise transpired into the sky, for every acre of forest that has been properly thinned.
What is stopping other communities in America’s arid west from following suit? Nothing, other than a mind-set among many who think that if a dozen trees are good, 100 are better. Meanwhile, to replenish the streams before they dry up, others have to accept that chopping down trash trees to prevent conflagrations, and thereby preserve the forests, is no bad thing. As the Wesleyan ecologists admit, “We lifelong tree-huggers must learn when and where to let go.”