Editors' note: This blog post was written by Joe Landsberg and Richard Waring. new book, so we encourage you to buy it), but let’s enlarge a little on those benefits. Obviously, they vary with forest type and location. Forests may not prevent floods when there is extraordinary precipitation, but they can and do stabilize catchments and watersheds. A great many landslips, all over the world, can be attributed to the removal of forests from slopes. Their role as sponges, holding water to be released gradually (and cleaned!) is not in question.
Tree plantations can be more susceptible to disease because they are monocultures. Photo by Tourism Victoria, used under Creative Commons licensing.The amazing biodiversity of tropical forests is immensely important. Those forests are the source of a great many of the medicinal (and other) drugs that we use, and the range of plants provides a gene pool that may hold the solution to some of the problems that we are generating in monospecific plantations, with their limited genetic base and consequent susceptibility to disease or insect attack. The temperate mixed forests that still cover large areas in the United States are also possible sources of invaluable genetic variation. The biodiversity of forests includes the wildlife that lives in them and passes through them seasonally—all sorts of birds, animals, and insects: the web of life. All important to a well-functioning planet. There is no question of the importance of forests in terms of carbon storage. On a global scale it’s massive, and very important as a buffer against rapidly rising carbon dioxide concentrations in the atmosphere. However, we do have to realize that the carbon is not stored forever. Plants respire and release carbon dioxide; biological material breaks down, releasing the carbon that is its major component. If we want to calculate the amount of carbon that would be stored by a forest in a particular location and its turnover time, we would have to have information about climatic conditions in the area and the forest type and age.
Forests in the Amazon and elsewhere help keep the planet cool. Photo by CIFOR, used under Creative Commons licensing.Direct mitigation of global warming by forests is largely a matter of the cooling effects of large areas of forest in hot regions. The physics are straightforward and the implications immense. For example, if the whole Amazon Basin were to be cleared, the already dangerous temperature rises caused by human activities would be increased by several degrees. And of course, its not just the Amazon where transpiration keeps the air cool; similar benefits can be felt along tree-lined streets in cities. It’s impossible to put values on aesthetics. We all have our own ideas and will all differ in the value we might place on beautiful forest scenery, or hiking in forested areas or (particularly in Scandinavia) collecting berries and mushrooms. But the value individuals might put on these things will be different from the value put on them by society as a whole. In the extreme case, if parts of a forest are held to be sacred by some people, to them those parts will be priceless. More generally, the amount people might be prepared to pay in additional taxes to fund the management of national parks and forests, may be strong indicator of their perceived economic value. Most economists are well aware that the demand for any product is influenced by the biases, emotional judgments, and subjective values of the product's consumers, which is very much the case in relation to the aesthetic values of forests. But it’s probably fair to say that the uncosted benefits are enormous—almost certainly, in aggregate, far beyond the straightforward economic values. It would be to the benefit of us all if that message was reiterated, loud and clear, to anyone who could influence, or bring pressure to bear on, those responsible for the ongoing destruction of forests round the world. It isn’t just a matter of feel-good, green tree hugging. It’s really important for all of us!