In their book, “Global forests: issues for six billion people”, Laarman and Sedjo (1992) surveyed forest inventories and issues of a decade ago, and offered some projections of (generally) short-term future supply and need for wood and other important services provided by forests. When considering the need for more-productive forest plantations, one needs to think of more-distant futures. Predicting the future, particularly decades or even centuries ahead, is hardly an exact science. Acknowledging in advance that all such predictions are likely to be wrong, and many badly so, I will use the creative thinking of Sutton (1999, 2000) to provide a qualitative framework for thinking about the future of plantation forestry. The need for more (or fewer) forest plantations can be modified by increasing or decreasing the productivity of the forest plantations, the topic of this thematic paper.
If Earth’s human population is reduced to below about 4 billion and stays below that number, then those people can probably continue to meet their wood needs much as they have recently, and still have a greatly improved standard of living. Sutton (op.cit.) noted, perhaps optimistically, that Earth’s human population may soon reach 10 billion people and stabilize at about that level. If it continues to increase much beyond 10 billion, then new and presently unimaginable ways of supplying their needs will have to be found. Sutton’s estimates of the needs for wood of 10 billion people seem capable of being satisfied using our present knowledge of indigenous forests and plantations.
For his low estimate of future wood needs, Sutton used recent average per-capita wood consumption, approximately 0.6 cubic meters of wood per year. That led to a world demand of 6 billion m3 per year for 10 billion people. He used a recent average harvest of 3.5 billion m3 per year, leaving a future deficit of 2.5 billion m3 per year. With about 80% of that 1990s harvest coming from indigenous forests, and given various increasing restrictions and other demands on indigenous forests, he estimated that harvest from them could not be increased by more than about 0.3 billion m3 per year. An additional 0.2 billion m3 per year will probably come from new forest plantations now planted, but not yet of harvestable age and thus not contributing to annual-harvest statistics. That left 2 billion m3 per year shortfall. He then calculated that, if average harvest productivity of new forest plantations would be 20 m3 per hectare per year, it would take an additional 100 million hectares of forest plantation to meet expected demand.
Sutton also considered the likely possibility that energy will become relatively more expensive. Since wood is highly energy-efficient compared to such alternatives as bricks, cement, plastic, steel and aluminum (which also, contrary to wood, are unrenewable), he reasoned that per-capita use of wood might therefore increase from its recent 0.6 m3 per year towards and perhaps beyond the current U.S. average of about 2.3 m3 per year. That would require about 1.4 billion hectares of forest plantation, which would cover about 10% of Earth’s land area, plus 2.6 billion hectares in indigenous forests, totaling 28% of Earth’s land surface in forests. Other papers in this and future analyses will no doubt provide more accurate figures but, as a qualitative basis for planning, Sutton’s estimates seem a reasonable beginning. A total of something near 2.6 billion hectares of indigenous and planted forests should provide enough wood, wood products, and other forest services such as water, wildlife habitat, and recreation to allow future civilization to work well.
In a recent book, Diamond (1999) has described the relative success of different cultures and civilizations as related to their historic access to plants and animals amenable to domestication, to the subsequent spread of the domesticates, and to the knowledge and technology that developed as a consequence of being able to abandon the hunting-and-gathering lifestyle. The domestication of many plants and animals began several millenia ago in the Fertile Crescent, in eastern Asia, in Central America and northern South America, and to a lesser degree elsewhere. These domesticated plants and animals had been taken to much of the world, and accepted by most of Earth’s peoples, by the beginning of the 20th Century.
The production of wood, and of other forest products and services, is an interesting exception to the general acceptance of domestication. As of the beginning of the 20th Century, most of Earth’s human cultures still derived their wood and other forest products in what was largely a hunting-and-gathering mode. They extracted these products from indigenous forests and then let nature replenish the supply, with little human input beyond occasionally protecting these forests from fire and excessive damage by insects. That is still largely the case today, as Earth’s human populations face the beginning of the 21st Century. This apparent anomaly is probably due in large part to the robustness of Earth’s indigenous forests, until recently providing an abundant supply of wood and regenerating to renew the wood supply and continue other forest services.
But there may be another reason. Diamond noted that having only a few species of local plants and animals amenable to domestication generally did not allow the local peoples to abandon a hunting-and-gathering lifestyle; it needed a sufficient number and variety of domesticated plants and animals to allow villages and food surpluses to develop. Furthermore, Diamond documented that the typical time lag between early domestication of plants and animals and the development of such things as written language and government organization was substantial, many centuries or even millenia for the cultures to adjust. We now understand that the Fertile Crescent and the Eurasian Continent did not have many forest-tree species that were good candidates for domestication, and that the middle Americas generally had abundant natural forests that met human needs without domestication. The most promising conifers for domestication were, and are, indigenous to North America, particularly western North America. The most promising angiosperms were, and are, indigenous to Australia, Papua New Guinea, and tropical and subtropical Africa and South America. These were among the very last areas on Earth to receive domesticated plants and animals, and the indigenous peoples there were, as a consequence, among the last to abandon the hunting-and-gathering lifestyle. Meanwhile, the Eurasians probably had found their forest-tree species as unpromising for domestication as had indigenous African, American, Australian, and Pacific Island peoples found their local food plants and animals to be.
Today, most of Earth’s peoples comprehend the advantages of domestication of useful organisms, and we have also identified many forest species that are amenable to domestication. If Sutton’s analyses of civilization’s near-future needs for wood and forests are anywhere near correct (Sutton 1999, 2000), Earth’s human population has reached a size and time when domestication of a modest number of forest species will be practiced on substantial areas of forest plantation.
