ALTITUDINAL ZONATION IN LATIN AMERICA
One of the most significant features of Latin America's climatic pattern with respect to the distribution of economic activity and population is a series of highland climates arranged into zones by altitude. This zonation results from the fact that air temperature decreases with altitude, at a normal rate of approximately 3.6 degrees F (1.7 degrees C) per 1000 feet (304.8 m) of elevation. At least four major zones are commonly recognized in Latin America: the tierra caliente (hot country), the tierra templada (cool country), the tierra fría (cold country), and the tierra helada (frost country). At the foot of the highlands, the tierra caliente is a zone embracing the tropical rain forest and tropical savanna climates discussed earlier. The zone reaches upward to approximately 2500-3000 feet above sea level at or near the equator and to slightly lower elevations in parts of Mexico and other areas near the margins of the tropics. In this hot, wet environment are grown such crops as rice, sugarcane, bananas, and cacao, often on a plantation basis. Populations of black Africans, brought to the New World as slaves, are concentrated in many of the tierra caliente zones.
The tierra caliente merges almost imperceptibly into the tierra templada. Although sugarcane, cacao, bananas, oranges, and other lowland products reach their respective uppermost limits at some point in this higher level, the tierra templada is most notably the zone of the coffee tree. In the tierra templada, coffee can be grown with relative ease (although by no means are all the soils suitable); at lower altitudes the crop encounters difficulties because of excessive heat and/or moisture. The upper limits of this zone -- approximately 6000 feet (1800 m) above sea level -- tend also to be the upper limit of European-induced plantation agriculture in Latin America. In its distribution, the tierra templada flanks the rugged western mountain ranges and, in addition, is the uppermost climate in the lower uplands and highlands to the east. Thickly inhabited sections occupy large areas in southeastern Brazil, Colombia, Central America, and Mexico. Although broadleaf evergreen trees characterize the moister, hotter parts of this zone, coniferous evergreens replace them to some degree toward the zone's poleward margins. In such places as the highlands of Brazil or Venezuela where there is less moisture, scrub forest or savanna grasses appear -- the latter generally requiring more water.
In brief, the tierra templada is a prominent zone of European-influenced settlement and of commercial agriculture. Six metropolises exceeding 2 million in population -- São Paulo, Belo Horizonte, Caracas, Medellin, Cali, and Guadalajara -- are in this zone, while two others -- Mexico City and Bogotá -- lie just above it. Four smaller cities that are national capitals and the largest cities in their respective countries are located in the tierra templada: Guatemala City, San Salvador, Tegucigalpa, and San Jose. Others, like Rio de Janeiro, which are situated at lower elevations, have close ties with predominantly residential or resort towns in these cooler temperatures.
The tierra fría (at 6,000-10,000 ft.) can be distinguished from the other zones by the related facts that it often experiences frost and is often the habitat of a native Indian economy with a strong subsistence component. European colonization in Latin American has driven some native Indian settlement upslope and into the tierra fría zone, although some major populations
-- the Inca of Peru for example -- had already selected upland locations for their settlement before the arrival of Columbus. These upland settlements are most extensive in Ecuador, Peru, and Bolivia, and this type of economy is also very evident in Colombia, Guatemala, and southern Mexico. The tierra fría is comprised of high plateaus, basins, valleys, and mountain slopes within the great mountain chain that extends from northern Mexico to Cape Horn. By far the largest areas are in the Andes, although areas in Mexico are sizable. The upper limit of the zone is generally placed at about 10,000 feet for locations near the equator and at lower elevations toward either pole. This line is usually drawn on the basis of two generalized phenomena:
- the upper limit of agriculture, as represented by such hardy crops as potatoes and barley, and (2) the upper limit of natural tree growth.
Another zone lies above the other three and consists of the alpine meadows, sometimes called paramos, along with still higher barren rocks and permanent fields of snow and ice. This zone is known as the tierra helada. It has some grains and animals (llama, alpaca, sheep) but is largely above the mountain flanks that are central to upland Indian settlement and agriculture. In the highlands of Latin America, the tierra fría tends to be a last retreat and a major home of the indigenous peoples, except in Guatemala and Mexico and is characterized by small settlements and what Europeans and Americans might consider rather primitive ways of life. However, certain valuable minerals like tin and copper are located here, attracting modern types of large-scale mining enterprises into the tierra fría and, the tierra helada of Bolivia and Peru.
[Source: Essentials of World Regional Geography 2nd Edition. Christopher Salter, Joseph Hobbs, Jesse Wheeler and J. Trenton Kostbade. NY: Harcourt Brace. p.464-465]
