"Waldgedankenexperiment"
(Forest thought experiments)
Humanity is engaged in a great experiment with the planets forests; unfortunately the experiment is not only bad science (no control planet), it is ill-considered. We are replacing large old complex forests with young simple fragments, in which fires are suppressed, large predators are removed, large herbivore populations are encouraged, exotic species are introduced, soil is compacted, and excessive biomass is removed. Our actions are experiments, whether we want them to be or not. Ignorance, denial, or cupidity cannot unmake this experimental course, which may be global and irreversible. There must be a way to refine the experiments, to minimize our impacts, to be less reckless, and to anticipate the outcome of our experiments before we finish performing them. Einstein and Infield suggest that knowledge of laws can be gained by the contemplation of idealized experiments created by thought, that is, Gedankenexperiment. For example, to address the equality of intertial and gravitational masses, that is, how to show that the problem of general relativity is connected with gravitation, Einstein imagined an elevator at the top of an incredibly high building, and then imagined what research would be done in this local environment. Such experiments might seem "fantastic" he decided, but they might help us to understand what we are trying to understand.
Although forestry is orders of magnitude more complex than simple physical systems, perhaps we could imagine and use such experiments to help us understand what is happening in and to forests. The thought experiments presented below are incomplete, but suggestive of what we could do.
Experiments
1. What if the US Forest Service reopened all sales with new rules. Interested parties would make proposals rather than bids. USFS would sell timber rights for 100 years. The buyer would pay the USFS fair market value for the timber. The size of the sales would be determined by habitat type (so there would be an equal number of small sales). The buyer could then log (within ecological limits) or preserve the area (depending on whether the buyer might be Georgia Pacific or Greenpeace). The buyer would be responsible for building roads, if any, to USFS specifications at buyer cost. The buyer would only pay taxes on detrimental (to the ecosystem and human ecosystems) environmental impacts, such as erosion, loss of fish streams, or aesthetic loss‹if any; no taxes would be paid on production or profits. Would this work?
2. Simplify forests by removing species. What would happen if we removed species one at a time, tracing all its connections, instead of removing the entire superstructure? Would we identify keystone species (or keystone mutualists or key linkages or taxa or processes) as things collapsed? Ronald Lanner asks if Whitebark pine is a keystone in some Boreal forests, providing pine nuts to nutcrackers and red squirrels, as well as fat for bears. Other possible keystones: Fig trees in Amazonian rainforests, beavers in North America, termites and elephants on the African savanna; sea otters, flies, snails, millipedes? It used to be that top predators were considered keystone species, but the systems continued (although diminished) after most of them were eliminated. Would each species be found to have a unique function in the community? How much redundancy would there be? Redundancy is necessary for diversity‹it can only come from existing pools of genetic and biological diversity, according to Chris Maser. Would it always be predictable?
In clearcutting, we have been simplifying the system by removing biomass, and expecting forests to pop up again ad infinitum. What if we removed different amounts of biomass in similar forests on each rotation‹at what point would the forests fail to return?
3. Model the forest by totaling all the behaviors of individual beings‹some computer modeling has started to do this with just trees, and although that is one way of getting some information, a forest is not just trees or even a collection of all individual beings. If we could add up all the activities of individuals (with enough people and enough time), we would have a lot of specific information about that forest. Very little could be applied to other forests, in other places, with other components, unless we were able to make general conclusions. Would the general conclusions be applicable to other forests?
4. Replace forest functions with mechanical devices. The machine metaphor dominates modern forestry. This metaphor, and the agricultural model, result in tree plantations, in which many of the functions of the wild forest have to be taken over by human ingenuity. On some tree plantations, many of the functions of a wild forest have to be duplicated. For instance, shade cards are used to protect young shade-intolerant species; plastic sheaths are used to protect bark from predators; fertilizer is used on young trees; and some trees are doped with mycorrhizal fungi. Extending this trend, modern forestry eventually may try to create an artificial forest. By taking this to a ridiculous extreme (the argument known as reductio ad absurdum), we might try to create an artificial forest with just one living organism, Douglas-fir trees. For example, we could replace the functions of nurse logs with gigantic nylon sponges. What artifacts or tools would we invent to replace the functions of woodpeckers, bats, insects, fungi, shrubs, or snags in a mature forest?
5. Costing out replacement of services. Suppose that we had to replace every function the forest provides with a human service. Could we afford it? The following sentence uses very approximate numbers. Pure water can be bought in supermarkets for $0.50-$2.00 per liter; canisters of clean air can be bought (in Tokyo for instance) for about $10 a liter, although air can be cleaned for much less; flood control can cost $11,000-$90,000 per linear meter; wind protection increases the costs of buildings; solar protection can cost $300 per square meter; fertilizer and pesticides can cost $40 a gallon; waste recycling costs thousands a day; climate moderation, i.e., cloud seeding, can cost $44,000 per day; recreation can cost $25,000-$25,000,000 per park; genetic modifications can run into millions. As you can guess, for an area of 50,000 people, the costs of replacing basic forest services could be billions of dollars per year. Many of these functions, like clean water, seem affordable to replace, but many such as climate moderation or soil creation are not affordable in any practical way.
6. What if we got tired of all that work and decided to save half the planet in wilderness? Imagine 6 billion square kilometers of forests set aside, with another 9 billion given over to the control of archaic cultures who reside in them. What changes would we really have to make? Substitution? We are good at that. Higher density living in cities? That trend has been evident for over a century; why not just plan it properly?
7. Imagining a planet without trees. Let us imagine that forestry and conservation both have failed, and the earth is a planet without forests and without trees in general‹except for a few artifacts kept in arboretums. For the first time in over a billion years, the planet is not sheltered, the climate is not moderated, and other plants, animals, fungi, and bacteria are not protected. Humans have made shelter for themselves, but we do not want to share it with mosquitoes or grizzlies. Have the ice caps melted? What is the shape of the global system? Are all human crops grown inside? Is the reduction of biodiversity causing unalterable (and yet unknown) changes? Can the forest ever be replanted? What kind of forests could live without fungi and bats and centipedes? Imagine what changes would occur in human psychology. (Have you ever seen the movie Silent Running with Bruce Dern? Good movie; bad future.) Would planting trees be required by law in our treeless world?
8. Forests have been changing for millions of years. A macrochronoscope in low orbit over the planet for the last several billion years would show forests moving like shadows over the landscape, with climate changes, glaciers, and shifts in moisture. The forests are connected to the land air and water; everything is constantly changing in a gigantic intricate web. The immense patterns are easy to detect with this imaginary device. On the ground, changes seem chaotic‹forests remember, are chaotic systems. A tree is embedded in a vast interconnected process that is creating an intricate and implicate order (physicist David Bohm¹s term meaning internally related). The patterns are persistent configurations of processes. Forests will continue to change, but now humanity is precipitating the change. Certainly, we should try to preserve the configurations that we value and need.
Summary: One thing philosophy has shown is that there is no single "right" answer to a question. The best response to a question is a hypothesis, a thought experiment. Through that, you can create explanations and discover answers in a dialog with others. Thought experiments can give us clues about what can happen (And then what? as Garrett Hardin always asks) and what is the likelihood of it happening. Unlike medical doctors or scientists, we cannot either wait or directly experiment (within a realistic time frame or scale). We cannot experiment at all in a traditional sense, where we hold most variables fixed, while changing one or two in experimental runs. Forests operate over very long time spans; furthermore, their historical nature means that they cannot be restarted.
Large-scale, long-term experiments are expensive and relatively few. Most experiments are short-range, small-scale, isolated, and detail dense. They do not make the hypotheses required for management of forests. Forestry management, because of uncertainties, lack of controls, age, uniqueness, is an uncontrolled, large-scale experiment. Thought experiments can refine the design of our larger experiments by suggesting better hypotheses.
Thought experiments can help us avoid being overwhelmed by details. Thought experiments can help formulate goals and interpret information appropriate to scale. The idea of science is to manage our experiences with generalities. Once the thought experiments are started they can be refined with conceptual or mathematical models, which can simulate the changes and evolution of changes. Computer-based models can permit complex explorations, as well as suggest patterns and further hypotheses. Through thought experiments and models, many of the dangers and expenses of our activities can be avoided.
Thought experiments are vital to understanding the complexity of forests. In practice, erring on the side of preservation‹the prudent and conservative course‹means minimizing the influence of human activities on the land. It means experimenting cautiously with new approaches to forestry and being properly skeptical about claims for sustainability. It means drastically reducing our demand for wood products, through conservation, reuse, recycling, and human population control, so that the greatest possible amount of natural forest can be left wild and degraded forest lands have time to be restored to health.
ed.
Bibliography
Bohm, David. 1980. Wholeness and the Implicate Order. London: Routledge and Kegan Paul.
Einstein, Albert and Leopold Infeld. 1966. The Evolution of Physics. New York: Simon and Schuster.
Hardin, Garrett. 1977. The Limits of Altruism: An Ecologist¹s View of Survival. Bloomington: Indiana Univ. Press.
Lanner, R. M. 1996. Made for Each Other: A Symbiosis of Birds and Pines. Oxford: Oxford University Press.