The Alto Paraná Atlantic forests form the interior wing of South America's Atlantic Forest, sweeping inland from southern Brazil across eastern Paraguay and into Argentina's Misiones province, covering seven Brazilian states from Minas Gerais and São Paulo down to Rio Grande do Sul. The dominant habitat is Atlantic semi-deciduous forest, where emergent trees can reach about 35 meters and the canopy is built largely from the families Lauraceae, Apocynaceae, and Leguminosae, with many trees shedding leaves through the winter dry season. The climate is subtropical, receiving roughly 1,200 to 1,600 millimeters of rain per year, and the dry season from April through September brings frequent frosts. The region is a biodiversity stronghold, home to the endemic black lion tamarin, but it has been one of the most heavily cleared forests in the Neotropics, reduced by more than 90 percent of its original extent. For gardeners in mild subtropical climates, this is the native home of laurel- and legume-family trees adapted to a pronounced wet summer and dry, frost-prone winter.

The Araucaria moist forests stretch across the highlands of southern Brazil, spanning the states of São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul, and reaching into Misiones Province in northeastern Argentina. Their signature is the Brazilian araucaria (Araucaria angustifolia), a monkey puzzle conifer that rises in a tall emergent layer above a broadleaf canopy of laurel (Ocotea), myrtle, and legume trees such as Mimosa scabrella. Lying above roughly 500 metres on mountains and plateaus, the ecoregion has an oceanic, subtropical to temperate climate with no dry season, frequent winter frosts, and high annual rainfall. It shelters threatened and endemic wildlife including the brown howler monkey and the red-spectacled (red-spectacled amazon) parrot, yet much of the original forest has been cleared and only a small fraction is protected. For gardeners in suitably cool, frost-touched climates, the emblematic Araucaria angustifolia is itself a striking ornamental conifer native to this region.

The Atlantic Coast restingas form a chain of coastal sand forests strung in well-defined enclaves along Brazil's Atlantic coast, running from the country's northeast to its southeast and from the tropics into the subtropics. These restingas grow on low-elevation plains of sandy, acidic, and nutrient-poor soils, supporting a five-to-fifteen-meter Atlantic forest of medium-sized trees and shrubs rich in the myrtle, legume, and spurge families, with vegetation ranging from low scrub to taller stands. Because the ecoregion stretches across a long latitudinal gradient, its climate shifts from tropical in the north to subtropical in the south. It shelters notable wildlife including the flagship red-tailed Amazon and the endemic Santa Cruz dwarf frog, yet the habitat has been reduced by more than 90 percent, with urban expansion the chief threat; surviving fragments are safeguarded in protected areas such as Jurubatiba Sandbank National Park.

The Bahia coastal forests stretch along a roughly 150-kilometer-wide belt of eastern Brazil's Atlantic coast, spanning the states of Bahia and Espírito Santo from near the Itapicuru River south to the Itapemirim. They form part of the larger Atlantic Forest, with Atlantic evergreen moist and semi-deciduous broadleaf forests as the predominant vegetation, including several species of Inga, bambusoid grasses, and the Paissava palm growing on nutrient-poor yellow-red soils. The climate is hot and humid, with rainfall of about 1,200 to 1,800 millimeters spread fairly evenly through the year, though the southern reaches see a drier stretch from May through September. The ecoregion is extraordinarily rich in endemic plants, birds, primates, and butterflies and shelters threatened wildlife such as the maned three-toed sloth and the golden-headed lion tamarin, yet it has been reduced by roughly 95 percent of its original cover, making it one of the most endangered habitats in Brazil.

The Bahia interior forests stretch across eastern Brazil, spanning the states of Sergipe, Bahia, Minas Gerais, Espírito Santo, and Rio de Janeiro as the inland wing of the Atlantic Forest, set between the coastal forests and Brazil's drier interior. Their dominant cover is seasonal moist to semi-deciduous forest, with characteristic trees including Cavanillesia, mahogany, and many legumes, alongside lower-canopy vine forests known locally as mata de cipo. The climate is tropical and semi-humid, with average annual rainfall between roughly 1,000 and 1,750 mm, mean annual temperatures of about 18 to 22 degrees Celsius, and a marked dry season of three to five months. The region shelters notable endemics such as the Coimbra-Filho's titi monkey and the northern muriqui, and the Mata do Passarinho Reserve here harbors the Stresemann's bristlefront, described as the rarest bird on the planet. It is among the most fragmented ecoregions of the Atlantic Forest, with few remnants larger than 10 square kilometers and only a small fraction under formal protection. Gardeners may recognize the prized Brazilian rosewood (Dalbergia nigra), a threatened timber tree native to these forests.

The Bolivian Yungas blanket the eastern Andean slopes of west-central Bolivia, reaching into a small portion of extreme southeastern Peru, where they form a transition zone between the Southwest Amazon moist forests below and the high Andean puna above. Spanning elevations from roughly 400 to over 3,500 metres, the ecoregion is a mosaic of montane cloud forest and other evergreen forest, with Chusquea bamboo characteristic of areas disturbed by landslides. Epiphytes are abundant, including bromeliads, orchids, and tree-ferns (Cyathea) draped across the canopy. Fog and rain carried in on the northern trade winds keep humidity and precipitation high, sustaining these cloud forests. This Neotropical moist broadleaf forest holds notably high endemism, sheltering range-restricted vertebrates alongside the spectacled bear, jaguar, and lowland tapir, and nearly half of it now lies within protected areas such as Madidi and Carrasco national parks.