The Atlantic Forest region includes forests of several variations.
The Atlantic Forest is unusual in that it extends as a true tropical rainforest to latitudes as high as 24°S. This is because the trade winds produce precipitation throughout the southern winter. In fact, the northern Zona da Mata of northeastern Brazil receives much more rainfall between May and August than during the southern summer.
The Atlantic Forest is now designated a World Biosphere Reserve, which contains a large number of highly endangered species including the well known marmosets and lion tamarins. It has been extensively cleared since colonial times, mainly for the farming of sugar cane and for urban settlements. The remnant is estimated to be less than 10% of the original and that is often broken into hilltop islands.
The Amazon Institute is active in reforestation efforts in the northeastern state of Pernambuco, Brazil. During 2007, Joao Milanez and Joanne Stanulonis have planted 5,500 new trees in the mountains commencing with Gravata, adding to the precious little, ancient forest left.
During glacial periods, however, the Atlantic Forest is known to have shrunk to extremely small refugia in highly sheltered gullies, with most of the land area more recently occupied by the characteristic Atlantic Forest being occupied by dry forest or even semi-desert. Some maps even suggest the forest actually survived in moist pockets well away from the coastline, where its endemic rainforest species mixed with much cooler-climate species. Unlike refugia for equatorial rainforests, the refuges for the Atlantic Forest have never been the product of detailed identification.