among them are further alternatives to destruction. In terms of food sources we already exploit tropical plants as sources of oils, fats, carbohydrates (sugars as well as starches), and proteins, but the current number of species that we use for food is very small. Discovering potential forest crops is going to require a massive research effort, but we can expect some shortcuts. These are outlined below.
First, we have a great potential source of insights in ethnobotany and ethno-zoology. Populations of humans throughout the world have existed in essentially harmonious relationships with tropical rain forests for centuries. Many of these relationships involved sustained yield subsistence use of the forests, and the Mayans produced a surplus of foodstuffs without destroying vast areas of forest. There are thus a wide range of peoples with invaluable knowledge about plants and animals. This knowledge may not be expressed in the terminology of modern science; it may be interlaced with magic, myth, and superstition, but it is certainly extractable. Just as certainly, its extraction is a matter of extreme urgency, since the folkways of forest peoples are disappearing more rapidly than the plants and animals that they have learned to exploit. In Part 2 of this volume, Nations, Farnsworth, Iltis, and Plotkin address various aspects of our need to utilize traditional knowledge—knowledge that is threatened and fragile. It is not merely knowledge of species but also knowledge of practices of husbandry, gardening, and agriculture. In Chapter 41, Altieri argues persuasively for the modern applications of ancient systems of mixed cropping as means of ex situ preservation of diversity. In addition to traditional knowledge, there is another shortcut to research into alternatives. This second method is implied in much of what I have already argued above. We have, in my opinion, a virtually untapped resource in the insights of tropical biologists. Experienced tropical biologists are potentially a source of major advances; they should be able to identify systems that are sources of evolutionary strategies that are preadapted to nondestructive parasitization by humans.
To apply such intuitions is going to require a change of attitude on the part of many academic biologists. They will have to recognize that elegant theoretical generalizations, intellectually exciting and satisfying as they may be, are not their only responsibility to science and society. We must become concerned about the future of tropical mankind, even if only because this is the only way we can preserve tropical nature. Janzen’s application of his extensive theoretical insights to the practical problems involved in regrowing tropical forests is a shining example to us all (see Chapter 14). The involvement of several Smithsonian biologists in research on alternatives to destruction is another excellent sign. We should also realize that sciences other than biology may be able to make substantial contributions to halting environmental destruction. An incalculable pressure is exerted on forests worldwide by fuelwood gathering. Eckholm (1975) has estimated that 1.5 billion people derive more than 90% of their fuel needs from wood, while another billion derive at least 50% from wood. Most of these people use extremely inefficient stoves, many with efficiencies less than 10%. The invention of an efficient and inexpensive wood-burning stove could greatly reduce the subsistence pressures on tropical forests.
While all the initiatives and possibilities mentioned above give cause for hope, although certainly not cause for optimism, there is still another area from which