It may sound antithetical to what we usually hear about climate change, but cutting down some trees could actually be a good thing for our environment, according to new research.
Trees provide natural carbon storage, and cutting them down leads to a huge increase in greenhouse gas emissions. But a pair of scientists at Dartmouth College plan to present new research this week that suggests that, in some snow-covered places in the world, cutting down trees might have a net benefit for the climate because of the cooling effect the snow provides.
Let's back up for a minute and first explain what they mean. That requires understanding the basics of albedo -- which to put it simply is the amount of solar energy reflected off a surface. Surfaces that are covered in snow are white, and they reflect more sunlight, which has a cooling effect. Surfaces that are darker in color, like forests, absorb more light and are warmer. Think of snow like a mirror, bouncing heat back off into space.
The new research -- from David Lutz, a post-doctoral researcher at Dartmouth, and Richard Howarth, a professor of environmental studies at the school and the editor of the journal Ecological Economics -- finds that in some areas where there's lots of snow, the benefits of open spaces where the snow can reflect the sun's energy could outweigh the carbon-storage benefits of the standing trees.
"If we're accounting for carbon, trees are worth more standing than they are cut down," Howarth told The Huffington Post this week, ahead of their presentation at the American Geophysical Union conference, the largest annual meeting of earth scientists. "The issue there is, it's not just the carbon storage. It's also the direct impact of what the surface characteristics of the landscape are."
Their study focuses on the White Mountain National Forest, in central New Hampshire. The forest has high elevations, lots of snow and trees that don't grow very fast. It's a place, Howarth says, that has a "lower potential for carbon uptake," but "a lot of potential for the albedo effect." The researchers used an integrated climate and economic model to assess the values of timber, albedo and carbon, and found that including a value on albedo would justify shortening the rotation periods in the planting and harvesting of certain species of trees in some areas. While this study looks at New Hampshire, the scientists think the study could be relevant for similar areas in the northern U.S., Canada, Russia and the Nordic countries.
This is important in the context of efforts to curb deforestation, or the cutting down of trees, and incentivizing reforestation. Creating a system that puts a monetary value on forests and providing motivation to end deforestation is one of the cornerstones of international climate policy. But the paper argues that, rather than just thinking about the value of carbon storage for the climate, there are other things that need attention, too. The research gets at this whole idea of "ecosystem services" -- that there are a lot of benefits that nature provides to humanity that are easy to take for granted, like storing carbon, or providing habitat, watersheds and coastal protection. A basic valuation of a forest might only include its monetary worth as timber, but a more complex calculation of ecosystem services would take into account a wider range of values derived from the forest.
The researchers argue that there needs to be a broader approach to how we think about and measure those services. "If we really care about using forests to mitigate climate change, when you only look at one thing ... it sometimes leads to unintended consequences," Lutz said. "That's what you see when you don’t incorporate albedo."
"Sometimes you incentivize some practices that from a climate prospective are inappropriate, or have the opposite effect of what you actually want," he continued.
To be clear, the researchers aren't suggesting that we clear-cut all the forests. Rather, the paper argues that sustainable forestry practices -- such as selective trimming, or harvesting in a rotation -- might provide positive climate impacts.
The next steps, the researchers say, will require them to also look at how snowfall patterns might change in the future, thanks to climate change. Less snow coverage could reduce the albedo. They are also looking to apply the framework they've developed to research in other regions, and then draw conclusions about what sustainable management might look like. It's one of those research projects that raises more questions than it answers, in many ways -- and is likely to cause a stir at this year's AGU meeting.
"From a climate perspective, it's not at all clear that focusing on carbon alone is getting it right," Howarth said. "There are cases where an open field may be a good thing."