In the battle to save the planet, trees are on the front lines. The act of planting trees, as thoroughly detailed in this book, has broad societal effects that go far beyond forest boundaries and city limits. Against the backdrop of the many developments contributing to the environmental degradation of the planet—shrinking forest cover, cropland degradation, growing population, accumulation of greenhouse gases, and a thinning stratospheric ozone layer—no single action can turn the tide. Yet, planting trees and nurturing them to maturity is one thing an individual can do to put society on the track to a sustainable future.

The advantages for the local community or city are readily apparent. Tree-lined streets are inviting and aesthetic, and urban forests provide a local getaway for city dwellers who routinely spend their weekends in search of wooded seclusion. These obvious benefits only hint at the broader implications. Livable cities can be energy efficient, enticing people to live closer to their jobs and to stay in the area during their leisure time rather than trying to escape at every opportunity. The trees that beautify also moderate city temperatures, reducing energy consumption for air conditioning and making summer heat less oppressive.

Tree planting also fosters community spirit and pride, bringing people together for a meaningful purpose that can build the bridges and promote the understanding that brings the neighborhood together. The initial efforts of the tree planters compound themselves as others find in the trees a deeper appreciation of the community as well as natural beauty. It is the beginning of the formation of new values that is the foundation for citywide transformation. The newly organized group can further push for bike paths, improvements in public transportation, and changes to make the area less congested, less polluted, and more livable.

Global deforestation is proceeding at an appalling rate, estimated at 150 square miles daily. Besides leading to the extinction of thousands of plant and animal species each year, deforestation contributes to greenhouse warming. Trees that are growing remove the primary heat-trapping gas, carbon dioxide, from the atmosphere, using it to produce wood in their growth. Cutting down trees begins the process of releasing carbon back into the atmosphere. If the area is not reforested, there is a net buildup in carbon dioxide. Worldwide deforestation currently accounts for roughly one-fourth of the carbon dioxide released into the atmosphere.

Although deforestation is primarily a problem in the tropics, industrial countries are still the primary source of carbon dioxide, due to the use of fossil fuels and greenhouse gases such as chlorofluorocarbons and nitrous oxide. With a business-as-usual scenario, the buildup of these gases in the atmosphere is projected to cause a rise in global temperatures of five degrees Fahrenheit by late in the next century. Such a change would cause a major disruption of natural ecosystems and agriculture and result in the flooding of coastal areas. Reversing the deforestation of the earth can slow global warming as trees take carbon dioxide out of the atmosphere, thus serving as a sink for excess carbon dioxide. 

Trees affect regional climates because of their part in the hydrological cycle. In one study, researchers found that three quarters of the rain that fell in a forested region of the Amazon Basin was returned to the atmosphere through evaporation and transpiration from the trees, with only one-quarter of the rainfall leaving the site as runoff into the streams to return to the ocean. The moisture recycled into the atmosphere replenishes clouds, moving the precipitation further inland. On deforested land, the ratio of evaporation-transpiration to runoff is roughly reversed, with three-quarters of the rainfall leaving the land. In vast areas of the interior of Africa, shrinking tree cover has seemingly weakened this link in the hydrological cycle, resulting in reduced rainfall and more frequent drought.

The increase in runoff from deforested slopes is a disaster for communities downstream. Without the trees to slow runoff, the rain carries away topsoil and can cause flooding. In India, the frequency of severe, crop-damaging floods has more than doubled since 1960. In the Philippines, extensive logging for tropical hardwoods has resulted in flooded agricultural land as well as irrigation reservoirs nearly filled in with the soil that eroded from once-forested land.

In many countries today, winning the battle against environmental degradation and economic decline depends on planting trees and planning families. Unfortunately, although much of the Third World has recognized the need for reforestation, successful efforts to reverse the loss of forests are rare indeed. South Korea, which has reforested its once-denuded hills and mountain sides, planting an area of fast-growing pines roughly two-thirds its area in rice, is the only developing country to reverse its deforestation. Among the industrialized nations, Australia has announced a major tree-planting program for the decade to restore two-thirds of the tree cover lost since European settlement, around 1 billion trees, and the United States has vaguely defined plans to plant 10 billion trees—a laudable goal if achieved.

Every tree planted is another step forward in the battle to save the planet, not only because of its environmental contributions, but because individual actions help to build the political momentum needed to push governments to take broader action. TreePeople is a pioneer in this area. Started in 1973 by a fifteen-year-old boy with a love of planting trees, its initiative has grown and grown, to the point where Los Angeles is adopting its plan to forest the entire city.

In this book, The Simple Act of Planting a Tree, TreePeople shares with us years of practical experience in planting trees in urban settings. From it, we can learn not only how to plant trees and nurture them until they mature, but how to bring nature into the urban environment, how to rebuild a sense of community, and how to make a difference in a world in need of change. This book is about changing the way we view our environment and the world.

Lester R. Brown
Worldwatch Institute