The pace of transformation increased during the first half of the twentieth century. In the Western world demands for timber accelerated. New uses (pulp, paper, packaging, plywood, chipboard) and relatively little substitution of other materials boosted use, while traditional uses in energy production, construction, and industry continued to loom large. The indispensable and crucial nature of timber in many Western economies gave it a strategic value akin to that of petroleum in economies today. In the tropical world the massive expansion of population by more than half a billion on a base of 1.1 billion resulted in extensive clearing for subsistence, accompanied by an expansion of commercial plantation agriculture. In all perhaps 2.35 million square kilometers of tropical forest were lost between 1920 and 1949.The only encouraging feature in the global picture during these years was the reversion of farmland to forest. This had begun in the eastern United States with the abandonment of “difficult” and hard-to-farm lands in New England in favor of easier-to-farm open grasslands, and continued with the abandonment of some cotton and tobacco growing lands in the southern States. A similar story unfolded in northern Europe with “marginal” farms.
The most publicized deforestation—the deforestation everyone thinks of when the word is mentioned— occurred after 1950. Since then the temperate coniferous softwood forests have about kept up with the demands of industrial societies for supplies of timber and pulp. But the focus of deforestation has shifted firmly to the tropical world. Here, better health and nutrition have resulted in a population explosion and an additional 3.5-4.0 billion people. These are often landless people who have moved deeper into the remaining forests and farther up steep forested slopes. They have no stake in the land and therefore little commitment to sustainable management. In addition chain saws and trucks have moved felling from the province of the large firm to the enterprising individual. Since 1950 about 5.5 million square kilometers of tropical forests have disappeared, Central and Latin America being classic examples. In addition, the tropical hardwood forests are being logged out for constructional timber at a great rate, while wood is cut for domestic fuel in prodigious quantities in Africa, India, and Latin America. Globally fuel wood-cutting now roughly equals saw timber extraction—about 1.8 billion cubic meters annually compared to 1.9 billion cubic meters. Cutting wood for fuel is forecast to rise rapidly in line with world population increase.