The constitution of the territory, the surface morphology resulting from the long labor of the endogenous and external forces, the climatic differences lead to divide Mexico into various natural regions.
The coastal region of the Atlanticfirst includes the strip of Tamaulipas, which between the Río Bravo and Tuxpán continues the formation of southern Texas with an almost uniform plain, covered, in the arid part of the north, by coppice and thorny shrubs, replaced by richer plant formations in the section wetter southern. Follows the coast of Veracruz, where the plain narrows a lot, but, due to the wetter climate, the lush vegetation takes on the appearance of an impenetrable jungle. In Tabasco the plain, always covered by dense jungle, is widening and is followed inland by a strip of undulating country on which the equally impenetrable virgin forest develops. Finally in the Yucatán peninsula the plain reaches its maximum development,cenotes). The northern coastal section, arid and covered with coppice, offers ideal conditions for the cultivation of the agave sisalana (henequén) on which the wealth of the state of Yucatán depends.
The Pacific coastal region is of lesser importance because it is much narrower and suffers from aridity, especially towards the N., in the narrow coastal selvedges of Baja California, Sonora and Sinaloa. For Mexico 1997, please check aristmarketing.com.
The region of the eastern outer slope embraces the tiered territory of the NE. between the northern border and the parallel of Tampico, in which the superficial erosion of the younger rocks has caused the formation of gentle steps made even less steep by the floods of the rivers, and in which, due to the rather arid climate, the vegetation is reduced to thorny shrubs (mesquite) and few grasses: it also includes the most arid and steep side of Veracruz and complicated by extensive lava flows and large volcanic cones; in it, thanks to the climate richer in rains and warmer, the erosion of surface waters becomes more energetic, but the vegetal mantle acquires an enormous development, so that the Veracruz escarpment is one of the richest agricultural regions of Mexico, being able to grow, at different altitudes, both tropical products (sugar cane, coffee, tobacco) and cereals from the temperate zone.
The external Pacific side, more wild on the whole, is formed by the bare and deeply engraved sides of the western Cordillera which falls on the short coastal plains; in Sinaloa and Sonora the slope is less steep and includes lower and hilly parts, but it is equally inhospitable and of little economic value due to the desert climate.
The highlands region occupies the largest part of the Mexican territory and from the structural point of view it should be divided into only two zones, separated by the Tehuantepec isthmus, namely the largest northern plateau, extending from the border of the United States to the region of Oaxaca, and the transistmic highlands of Chiapas.
But the great northern plateau is not uniform and there are four sub-regions: the first is the Sonoran desert and Baja California, where the surface morphology is the result of a long period of erosion in an arid climate, with short low-drainage plains at the sea, limited by isolated cocuzzuli and by sections of chains: the vegetation, very scarce and discontinuous, forms oases of herbs or succulent and thorny plants, separated by large desert tracts. The second subregion is that of the Sierra Madre Occidental, formed, as mentioned, by a bundle of chains roughly parallel to the Pacific coast, but whose flanks have different aspects: the western one has a very accentuated slope and engraved by gorges and gorges within which the waters precipitate rapidly downwards, whereby the streams, thanks to the strong difference in height, are endowed with a great erosion force and carry the debris up to the coastal plain or into the sea, the eastern one instead gradually descends towards the plateau, and its rivers, poor d ‘water and intermittent, they end in closed tanks located at a rather high level, and therefore have a lower speed and a lower erosive capacity. The vegetation ranges from the expanses of grasses and mesquites of the lower and more arid slopes of the northern part,
The third subregion includes the arid plateau of the north – east, which in the western part leaning against the Cordillera is a region of mountains with rounded peaks, covered with horizontal layers, interposed with large, less elevated plains; the eastern part, on the other hand, is characterized by closed internal basins that end in real depressed basins called bolsones, of which the best known are those of Mapimí. A desert flora of herbs, cacti, yuccas and mesquites grows here, replaced by cotton plantations where artificial irrigation is possible, as in the Bolsón de Mapimí. The great central plateau holds the fourth place which, from a human point of view, is the most important part of Mexico as it is home to the best agricultural land and especially the cereal region, as well as the main deposits of precious metals.
Limited to the south and east by steep slopes, the plateau is higher towards the west where it joins the Sierra Madre, while the passage to the arid region of the north-east is almost insensitive. The superficial morphology, very complex, presents next to more ancient reliefs, subjected to very long subaerial erosion, younger and higher volcanic mountains, which at least partly cover and dominate the oldest formations. In the midst of these mountains there are less elevated and flat areas, already occupied by lakes now in the process of drying up: the basin or Valley of Mexico is particularly famous. The vegetation varies according to rainfall and altitude. The high inland plains, poor in rainfall, are covered with grasses, the low slopes of the mountains are lined with coppice, while firs and conifers rise the higher and better exposed sides up to 3800-4000 meters; higher still there are meadows and the limit of permanent snow is about 5000 m. On the wettest slopes, forests of deciduous trees precede those of conifers.
Finally, the high lands of Chiapas constitute a small plateau just over 220 km wide. and with a maximum height of 2000 meters; to the south there are strong and well-marked folds, while to the north there are mountains with flat roofs in the middle of which considerable volcanic activity has taken place. The vegetation is formed by forests of deciduous trees, interrupted by grassy clearings that provide rich pastures.