The new data show forest carbon storage by region, with forests in the 11 Western states accounting for almost a third of the nation’s total. Forests in the West reach two extremes. Oregon, Washington, and southeast Alaska forests store the most carbon per acre of anywhere in the U.S., while those in Arizona, Nevada, New Mexico, and Utah store the least. Perhaps more important than the quantity stored, however, is the change from one year to the next. Expanding forests that each year tie up more carbon than the year before are carbon sinks, taking carbon dioxide out of the atmosphere as they build up wood, detritus, duff, and soil, whereas shrinking forests hold less carbon year by year, making them carbon sources.
According to a report [pdf] published by the Ecological Society of America earlier this spring, U.S. forests were a carbon source during the 19th century when people harvested wood for burning and building and cleared land to make way for crops, livestock, and development. Then around 1950 that trend reversed, as forests began to recover ground. Today, U.S. forests are still acting as a sink, but they’re approaching a neutral state as their carbon storage levels off. And in a frightening, self-perpetuating cycle, forests could actually turn back into a carbon source in response to climate change, the Ecological Society report says. Extreme weather like ice and wind storms, as well as fires and invasive species, are increasingly likely to disturb forests, replacing large old trees that hold a lot of carbon with new young ones.
Public forests of the West are more than pretty places to go hunting or hiking, more than a source of wood and clean water. If managed for carbon storage, they could also be tools in the fight to bring atmospheric carbon dioxide back down to a level of 350 parts per million. That’s a goal that needs to be embraced by everyone, tree huggers and non-tree huggers alike.
Emilene Ostlind is a High Country News intern.
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