A Global Pandemic of Tree Plantations

Like a scene out of a Mel Brooks movie, plantation forests have risen from the graves of old-growth forests. If you don’t believe me, visit an old-growth forest and then contrast that with a tree plantation to see, feel, and smell the difference. Old-growth forests like those of the Pacific Northwest, Coastal Redwoods, or Alaska’s Tongass rainforest are very diverse places from the forest canopy to the floor. The giant trees punctuate the canopy, while mid-aged trees populate the mid story, and a host of smaller trees, shrubs, and wildflowers blanket the lower levels. The floor is made up of living soils like fungal mats that stick to the roots of trees, including seedlings, helping them absorb water and vital nutrients so that young trees may someday join the rainforest giants. Nothing in these forests is wasted as life and death are joined at the hip. Snags—standing trees that die from natural causes—are vital to the health of the rainforest as they provide habitat for scores of insect-eating bats, birds, and small mammals keeping destructive pests in check. When they eventually fall to the ground, the decaying logs act as “nurse logs” nurturing seedlings on their surface and providing moist micro-sites for invertebrates, salamanders, and fungi. Now contrast this with a tree plantation produced by industrial clearcutting and then planted by foresters with just a few commercially-grown tree species. The young trees are all the same size and age, planted in stacked rows like corn fields. There is no canopy or mid story. Snags and down logs are vacant and the understory has a sterile appearance to it. In nature, complexity rules; in human-created plantations, simplicity is the norm. Complexity provides structure to a forest and habitat for wildlife. It gives a forest the ability to rebound from natural disturbances, which is especially important in times of climate chaos. Tree planting helps to reduce the net loss of forests globally. Much of this planting is through afforestation—the planting of trees in areas not previously forested—but replacing complexity comes with significant ecological costs. For instance, according to the Global Forest Resources Assessment of 2010, the area of planted forest is increasing while that of primary (unlogged forests) is crashing. In some regions, like South America and Oceania, nearly all the planted species are introduced. Afforestation efforts in Europe, where forests were nearly wiped out ages ago, include introduced conifers from North America not native species. Regardless of tree planting, there is a net loss of carbon dioxide from the system when old forests are cut down through the decomposition of logging slash, loss of carbon in soils, and transporting and manufacturing of wood products following a logging operation. Young replacement forests are therefore carbon dioxide emitters. This is especially the case on private lands where plantations may be logged again in a few decades. Young trees never become carbon-storing old-growth giants when they are repeatedly harvested. The United Nations jump started the Reduce Emissions from Deforestation and Forest Degradation (REDD) Programme. Developed countries pledge funds to prevent deforestation in carbon-storing tropical rainforests, however, there are no such limits on forest degradation in countries like the U.S. where all but nearly 5 percent of old-growth forests nationwide are gone. The zombie like rise of tree plantations along with deforestation globally has gobbled up large areas of intact rainforests. Based on estimates provided by the World Resources Institute, nearly half of the world’s largest intact forests are gone and some regions such as Europe have none or—like the continental U.S.—very few. The U.S. has some of the most important carbon sinks in the world: the temperate rainforests of the Pacific Northwest and Alaska. Intact forests are essential in efforts to combat global warming. They cleanse the air we breathe, store vast amounts of carbon, purify drinking water supplies, and provide a refuge for climate-sensitive species. We simply cannot afford to have the proliferation of tree plantations if we are serious about global warming and the many benefits that intact, old-growth rainforests provide.