The circumboreal belt of forest represents about 30% of the global forest area, contains more surface freshwater than any other biome, and has large tracts of unmanaged forests across the high-latitude regions of Canada, Russia, and the United States. It is typically comprised of coniferous tree species such as pine, spruce and fir with some broadleaf species such as poplar and birch. The boreal ecozone principally spans 8 countries: Canada, China, Finland, Japan, Norway, Russia, Sweden and the United States. In Brazil the name of the river that flows from Peru to its confluence with the Negro River is Solimões from the Negro out to the Atlantic the river is called Amazonas.The boreal forest (or “taiga”) is the world’s largest land biome. In Peru the upper main stream (fed by numerous tributaries flowing from sources in the Andes) down to the confluence with the Ucayali River is called Marañón, and from there to the Brazilian border it is called Amazonas. Although the name Amazon is conventionally employed for the entire river, in Peruvian and Brazilian nomenclature it properly is applied only to sections of it.
The first European to explore the Amazon, in 1541, was the Spanish soldier Francisco de Orellana, who gave the river its name after reporting pitched battles with tribes of female warriors, whom he likened to the Amazons of Greek mythology. The ecological consequences of such developments, potentially reaching well beyond the basin and even gaining worldwide importance, have attracted considerable scientific attention ( see Sidebar: Status of the World’s Tropical Forests). Significant mineral discoveries have brought further influxes of population.
Deforestation has accelerated, especially south of the Amazon River and on the piedmont outwash of the Andes, as new highways and air transport facilities have opened the basin to a tidal wave of settlers, corporations, and researchers. Since the later decades of the 20th century, the Amazon basin has attracted international attention because human activities have increasingly threatened the equilibrium of the forest’s highly complex ecology. This immense volume of fresh water dilutes the ocean’s saltiness for more than 100 miles (160 km) from shore.Īmazon River, South America. The flood-stage discharge at the river’s mouth is four times that of the Congo and more than 10 times the amount carried by the Mississippi River. It is estimated that about one-fifth of all the water that runs off Earth’s surface is carried by the Amazon. Although considered a part of Amazonia by the Brazilian government and in popular usage, it is technically a separate system. The Tocantins-Araguaia catchment area in Pará state covers another 300,000 square miles (777,000 square km). Stretching some 1,725 miles (2,780 km) from north to south at its widest point, the basin includes the greater part of Brazil and Peru, significant parts of Colombia, Ecuador, and Bolivia, and a small area of Venezuela roughly two-thirds of the Amazon’s main stream and by far the largest portion of its basin are within Brazil. The vast Amazon basin (Amazonia), the largest lowland in Latin America, has an area of about 2.7 million square miles (7 million square km) and is nearly twice as large as that of the Congo River, the Earth’s other great equatorial drainage system.