The Serra do Mar is the great escarpment that runs along the coast of south-eastern Brazil, a wall of forested mountains between the São Paulo plateau and the Atlantic, and crossing it is one of the main events of any ride from the city to the sea. The roads that climb or descend it, such as the Rodovia dos Tamoios, thread through dense Atlantic forest, one of the most diverse and most threatened ecosystems on earth. The trees are tall and wrapped in vines, bromeliads and ferns, and the air is thick with the smell of wet leaves and soil.
The area near Santa Branca and Jacareí lies in the Paraíba valley, on the plateau side of the range, where reservoirs and farmland fill the broad floor of the valley. From here the roads lead up and over the mountains toward the coast, and the change in scenery is rapid. On the plateau, the air is drier and cooler, with pasture and eucalyptus, and as the road rises into the forest, the temperature drops and cloud begins to gather. At the crest, the mist can be so thick that visibility falls to a few metres, and the road emerges below it into sunshine or a downpour.
The ride is demanding in the best way. The bends are tight and often blind, the surface can be wet and slick with moss and mud, and heavy trucks use the same lanes, so overtaking needs judgement. Wet weather is common, with sudden downpours, and fog is frequent in the mornings. Care is required on descents, where brakes can overheat and the road drops steeply, and the locals know that a clear day can turn into a grey one in minutes. Landslides sometimes close sections after heavy rain, so check the conditions.
Santa Branca, about two kilometres away, is a small town with basic services, and Jacareí, a city of over two hundred thousand, lies about eleven kilometres off, with plenty of fuel, food and repairs. There are few stations on the mountain, so fill the tank before the climb. Roadside stalls and small restaurants appear at viewpoints and sell snacks and fruit.
The wildlife in the forest is rich, with toucans, monkeys and many butterflies, though you will seldom see them from a bike. Stop at a viewpoint, if the clouds permit, and listen to the forest. It is a green, loud world.