Relief and drainage
The state’s relief has three distinct features: the plain, or coastal lowland; the mountainous highland; and the plateau of the interior. The coastal lowland—which is broken by occasional massifs or rocks that sometimes extend far into the sea—is narrower to the west, where the Serra do Mar compresses it against the sea. The mountainous highland comprises part of the Serra do Mar and, farther inland, part of the Serra da Mantiqueira, both of which run parallel to the coast in a roughly southwest-to-northeast direction. Some important tourist and holiday resorts—Petrópolis, Teresópolis, and Nova Friburgo—lie in this region. At 9,144 feet (2,787 metres) Agulhas Negras (Itatiaia) Peak is the highest point in the state.
The most important feature on the plateau is the Paraíba do Sul River valley. The river flows northeastward across much of the state before turning eastward to drain into the Atlantic. Coffee plantations were first developed in the valley in the 19th century. Smaller rivers and streams drain into Guanabara Bay or directly into the Atlantic. Rio de Janeiro includes about 370 square miles (960 square km) of coastal lagoons and other internal waters.
The state has a subtropical climate. The prevailing conditions along the coast are hot and humid and are characterized by summer showers. In winter the climate is modified by cold air masses from the south. The average daily temperature is generally above 72 °F (22 °C). The highland climate is characterized by mild temperatures that average below 68 °F (20 °C) because of the higher elevations.
Flora and fauna
Great forests originally covered the territory of the present state of Rio de Janeiro. From the 16th century indigenous peoples and European settlers alike began to clear large tracts of land for temporary cultivation, using the queimadas (slash-and-burn) technique. A succession of expanding sugar plantations, coffee farms, and sprawling urban centres obliterated most of the remaining forests. In the mid-20th century the Brazilian government began to reforest some highland areas, and national parks were established to protect the remnants of the original forest. Itatiaia National Park (1937), in the Mantiqueira Range, covers about 116 square miles (300 square km) of rainforest in both Rio de Janeiro and Minas Gerais states. Serra dos Órgãos National Park (1939) and the smaller Tijuca National Park (1961) are wholly within Rio de Janeiro.
Apart from these public parks, some patches of forest vegetation still survive on a few hillsides near the city of Rio de Janeiro, but these are disappearing as the urbanized area is gradually enlarged. On the Santa Cruz, Campo Grande, and Jacarepaguá plains, grassland prevails, whereas on the muddy coastland red, yellow, and white mangroves flourish.
The forests and wetlands support numerous animals, including ocelots, marmosets, and tortoises. Curassows, ouzels, whistling ducks, and other birds are also found there.