restricted access Chapter Nine: Plants Heal the Landscape

From: Green Planet

Rutgers University Press colophon
In lieu of an abstract, here is a brief excerpt of the content:

[171] chapter nine PLANTS HEAL THE LANDSCAPE A people without children would face a hopeless future; a country without trees is almost as hopeless. —theodore roosevelt The Forest Not Primeval Welcome to the tropical rain forest of Central America. Foliage grows luxuriantly everywhere; woody vines bind together the branches of tall trees. In what appears to be an undisturbed, primordial rain forest, a fine mist falls on the leaves and drips from their tips onto the walls of a Mayan ruin. Only six hundred years ago, very little of this rain forest existed. The Mayan building was once part of an extensive civilization, in which three-quarters of the landscape had been transformed into human habitations, centers of community activity, and intensive agricultural production. When, after flourishing for nearly a millennium, the Mayan civilization collapsed, its buildings and walls were reclaimed by the natural rain forest. We think the recovery was complete, but of course we do not know, as the “original” rain forest, from pre-Mayan times in this location, no longer exists for comparison. In fact, you cannot find an “original” forest anywhere. Or an original grassland or shrubland or desert. All of the natural habitats of the earth, determined by climatic conditions and defined by the plants that both grow in and shape them (chapter 8), have come and gone, and shifted in location, during just the past few thousand years. Sometimes this has been from the waxing and waning of human activity; sometimes it CH009.qxd 11/12/08 11:00 AM Page 171 has been from fires or other natural destructive events. But over and above all of these factors, the vegetation has shifted back and forth owing to the advance and retreat of glaciers during and after the most recent ice age. When Henry Wadsworth Longfellow wrote in his epic poem Evangeline, This is the forest primeval. The murmuring pines and the hemlocks, Bearded with moss, and in garments green, indistinct in the twilight, Stand like druids of eld . . . he was describing an Acadian forest that had not been there when glaciers covered the land a few thousand years earlier.The entire surface of the earth is covered with plants that are always shifting locations in response to changes in climate and to disasters and, more recently, to human disturbances. Nevertheless, natural habitats of plants and animals are not fragile crystals that can be easily shattered by one human error or stroke of natural bad luck.They form a web of ecological interactions and consist of a great diversity of species that actually make them strong, not fragile, and able to adjust to fluctuating and sometimes disastrous circumstances. This chapter is their story of dynamic survival and the essential role that plants play in it. Plants not only create habitats; they heal them after disasters. However, as robust as plants are in healing the disturbances of the landscape, there is only a finite amount that they can do. For millions of years they have successfully reclaimed the living landscape from glaciations , fires, landslides, and volcanic eruptions; for thousands of years, they have responded creatively to human disruptions—the fires we have started, the fields we have farmed, the woodlands we have chopped. As we saw in chapter 1, the recovery has not been complete.The healing of the landscape has sometimes left scar tissue. There is only so much upheaval from which the natural ecological communities can recover. Today, we are challenging plants with an extent of disturbance, and types of disturbance, to which they have never before been subjected. Plants can help to save us from the greenhouse effect (chapter 3), and from droughts and floods and soil erosion (chapters 5 and 7); they will green planet [172] CH009.qxd 11/12/08 11:00 AM Page 172 also heal up the injuries we inflict, if we allow them.To an ever increasing extent, we do not. Disturbance Strictly speaking, there is no such thing as a forest. “Forest” is the name we give to the set of species of plants and animals and microorganisms that grow together in one location. These species interact with one another, but they are not parts of a forest the way organs or cells are part of a body. If a disturbance such as a fire wipes them away, other species of plants, animals, and microorganisms live in the new environment created by the fire. Because of ecological changes that occur during the subsequent decades, the original...