We find ourselves not at the edge of a precipice, but beyond it. Climate change is altering the world as we know it, no matter how quickly we act to reduce our collective carbon footprint. But the worst impacts are still avoidable with natural climate solutions. Permanently protecting forests and allowing them to grow in landscapes free from direct human manipulation is proving to be one of the most effective and cost-efficient methods available to address the climate crisis. While wild nature has a right to exist simply for its intrinsic value, recent science is shedding peer-reviewed light on the exceptional carbon storage capacity of unmanaged land, and its equally important benefits for safeguarding biodiversity. In this short synthesis, ecologist Mark Anderson summarizes recent studies which demonstrate that in our fragmented, fast-developing world, wilderness offers the earth and its community of life the precious gift of time.
—Jon Leibowitz, Executive Director, Northeast Wilderness Trust
A long-standing debate over the value of old forests in capturing and storing carbon has prompted a surge of synthesis studies published in top science journals during the last decade. Here are five emerging points that are supported by solid evidence.
1) Trees accumulate carbon over their entire lifespan. Plants absorb carbon dioxide from air and transform it into carbon-rich sugars. These are then converted to cellulose to create biomass (trunk, bark, leaf) or transferred below-ground to feed the root-fungal networks. Over the long lifespan of the tree, large amounts of carbon are removed from the air and stored as biomass. Growth efficiency declines as the tree grows but corresponding increases in the tree’s total leaf area are enough to overcome this decline and thus the whole-tree carbon accumulation rate increases with age and size (Figure 1). A study of 673,046 trees across six countries and 403 species found that that at the extreme, a large old tree may sequester as much carbon in one year as growing an entire medium size tree (Stephenson et al. 2014). At one site, large trees comprised 6 percent of the trees but 33 percent of the annual forest growth. Young trees grow fast, but old trees store a disproportional amount of carbon…