(introduction...)

Management of forest ecosystems has always been one of the most difficult challenges presented to humans. During the agricultural revolution, societies inhabiting forest areas in Europe, the Middle East, and other parts of the world started clearing trees to prepare land for crop production. In Roman times, hundreds of thousands of square kilometres of Mediterranean forests with their deep and fertile soils were eliminated to make way for cereal crops, such as wheat and barley. In Sudanese Africa, during the first centuries of the Christian era, a considerable portion of forest gave way to locally domesticated sorghum and millet crops and itinerant cattle-raising. In America, many of the forests surrounding the valley of Mexico were gradually removed to make room for corn and bean farms. In Asia, rice paddies replaced the extensive forests of China, Indochina, and some of the largest Indonesian islands.

Despite this worldwide reduction in area, at the time of the industrial revolution forests still occupied nearly 30% of the continental landmass, typically concentrated in humid and subhumid areas. In the 1600s, more than half of Europe and more than 90% of the humid regions of North and South America were covered by trees. In Africa, although long-term human habitation had significantly reduced forest areas (mainly through burning), resulting in “savannization,” large tracts of land in humid and subhumid regions remained covered by forests.

In Europe, the industrial revolution brought about systematic and intense degradation of the forests. The main causes were the increase in population and the burning of firewood by industries and individuals. During the 18th and 19th centuries, new villages were established in less productive environments, such as steep and stony slopes in the cooler mountain highlands of the Alps, the Massif Central of France, and the Apennines in Italy; these areas were slowly converted to agricultural production, significantly reducing the forest cover.

In many areas of Europe, population growth outpaced the opening of new farmland. Often, this was simply because land was not available. In many cases, however, it was due to a concentration of land ownership in the hands of a few people. At the beginning of the industrial revolution, most of the surplus rural population had moved to cities to work in the new industries. However, European industries soon proved insufficient to absorb all the migrants. This prompted the migration to America, which by the end of the 19th century and the first half of the 20th century became intensive.

In North America, the arrival of millions of Europeans meant the opening of new forestlands for farming. New England was completely’ covered by forests in 1620 and largely deforested 150 years later. In the 18th century, more than 4 million hectares of Arkansas marsh and swamp forests were converted to farmland (Reisner 1986). Between 1848 and 1858, Minnesota’s population, next to the Canadian border, increased from 10 to 150 thousand (it was promoted from a territory to a state at this time). A similar situation occurred in the 1870s in the territory of Dakota (National Geographic 1986). By the late 1870s, more than half the temperate forests of North America had been eliminated, and the process continued for many decades. Because land had become scarce in the east, most new arrivals and many older settlers or their descendants moved west, clearing new land for agriculture.

In South America, most forested areas were in the tropics, particularly in the Amazon basin and the upper basins of the Parana and Orinoco rivers. Early deforestation of tropical ecosystems occurred during the colonization period along the northeastern coast of Brazil to make way for sugarcane plantations and, later, by the end of the 19th century, around Sao Paulo for coffee production.

The deforestation of mountain areas, which had begun in precolonial times, continued after European colonization, reducing forested areas to only the steeper or cooler slopes by the end of the 19th century. Well into the 20th century, however, a considerable portion of the continent’s extensive tropical forests remained virtually untouched. This delay in deforestation was probably due to the abundance of grasslands in the more productive temperate areas (the pampas). The only forested areas in temperate climates were on the slopes and narrow plains along the Pacific coast in central and southern Chile and in the highlands of the Planalto of southern Brazil.