Tree Community in Cunha, São Paulo, Southeastern Brazil A brief guide Photo: Luciano Candisani Gabriel Pavan Sabino Universidade Estadual Paulista “Júlio de Mesquita Filho” – UNESP, Campus Rio Claro Master’s Student in Biological Science (Plant Biology), School Of Biosciences. E-mail: [email protected] Tree Community in Cunha, São Paulo, Southeastern Brazil Tree Community in Cunha, São Paulo, Southeastern Brazil Introduction to the Brazilian Atlantic Forest Historically speaking, Brazil started its development at the Atlantic Forest. The fleet of the Portuguese navigator Pedro Álvares Cabral anchored in the region where the present-day State of Bahia is located. The Atlantic Forest is also the domain of Brazilwood, whose name was given to the country (Caesalpinia echinata Lam. - Fabaceae). The Atlantic Forest covers a large extent of the Brazilian coastline, at the Serra do Mar hillsides. Its original area of 1,200,000 km² of large-sized forest has been deforested and only 7% exist currently. The original distribution spanned over a continuous zone, from Rio Grande do Norte and Ceará (Northeastern Brazil) to Rio Grande do Sul (Southern Brazil). Due to the fact that it spans over many different altitudes and latitudes, the Atlantic Forest exhibits diverse formations and landscapes. The most remarkable of them is the Dense Ombrophilous Forest, a lush and biodiverse floristic formation located close to the ocean. Further inland, the forest exhibits formations where the plants lose partially their leaves, the Upland Atlantic Forest. Furthermore, in the Southern Brazilian States – Paraná, Santa Catarina and Rio Grande do Sul – a portion of the Atlantic Forest features the traits of the Araucária (Araucaria angustifolia Bertol. Kuntze – Araucariaceae) Moist Forest, or Mixed Ombrophilous Forest. It plays a key role in the stabilization of the coastal terrain, remaining the hillsides stable and preventing landslides. It has rugged topography and shallow soil and rocky outcrops are often visible. Such an exuberant forest is supported by high humidity levels which come from the ocean and stay at the Serra do Mar. About 70% of the Brazilian population lives in cities at a maximum distance of 200 km from the coastline and shares space with this biome, whose historical occupation harks back to the main economic cycles which led to an intense loss of the Atlantic Forest. After visiting this biome, Charles Darwin wrote: “There I saw, for the first time, a tropical forest in all its sublime grandeur - nothing but the reality can give an idea of how wonderful and magnificent this landscape is.” Page 1 Tree Community in Cunha, São Paulo, Southeastern Brazil The Serra do Mar State Park and the research in Cunha The Serra do Mar State Park (PESM) was created in 1977 and is considered to be the largest conservation reserve in the Atlantic Forest, covering 332,000 hectares. The kernel of the PESM Cunha, also created at the time, acts as an important area of maintenance and conservation of the biodiversity in predominantly altitude phytophysiognomies. Within the thematic project Biota/FAPESP (no. 03/12595-7 and 10/50811-7), two botanical researches have been conducted in the PESM Cunha. Each research has investigated the floristic and phytosociological¹ composition of tree species in four plots of 0.25 hectares, totaling 2 hectares. In every plots, all trees (including palm and fern trees) whose trunk diameter is at least 4.8 cm and whose stipe² is 1.3 m in height has been collected. It is interesting to remark that, even though the portions are very close to each other (about 500 m), they exhibit very different physiognomies. The study conducted by Morais et al. (not published data; plots marked by “U”) showed a physiognomy hitherto identified as “High Forest”. This area is composed by large-sized trees with a continuous canopy which is about 12 m in height (picture 1), located in a land with declivity. Picture 1. Overall look of the “High Forest”. (Photo: Gabriel Sabino) Page 2 Tree Community in Cunha, São Paulo, Southeastern Brazil The continuous canopy, associated with the intense competition for sunlight, usually furthers an unusual development of the crowns, which seem to be divided in the middle (picture 2). The understory³ exhibits an average density, probably due to the large amount of shadow provided by the crown overlaying. In some regions, there are rocky outcrops and the soil is considered to be shallow. Some emergent trees, mainly represented by the families Sapotaceae and Lauraceae, reach over 20 m, making it difficult to collect the material. In a Cloud Dense Ombrophilous Forest4, it is expected to see a physiognomy which is different from this portion. It is structurally more similar to the formations of Montane Forests5, mainly due to the large size of the trees. In this researched area, 2,092 individuals belonging to 38 families and 134 species have been found. The most common families regarding the amount of species were: Myrtaceae (25 species), Lauraceae (23), Rubiaceae (8) and Fabaceae (7). Picture 2. Tree with a half-crown in the “High Forest” of the “U” portion. (Photo: Gabriel Sabino) Page 3 Tree Community in Cunha, São Paulo, Southeastern Brazil The study conducted by Grillo et al. (not published data; plots marked by “S”), covering a region hitherto identified as “Low Forest”, showed a more expected structure for a cloud formation, with small-sized trees (about 8 m), often with sinuous trunks (picture 3) and a large density of epiphytes (mainly bromeliads and orchids). Picture 3. Vegetation with sinuous trunks in the “Low Forest” of the “S” portion. (Photo: Gabriel Marcusso) In the “Low Forest”, the land is more level and the sunlight penetrates the tree stratum much more easily. It is likely that these aspects contribute to a more expressive development of the understory. The latter one is considered to be dense and exhibits especially bamboo thickets and a large amount of bromeliads which, at some portions, cover densely the soil (picture 4). In this researched area, 2.523 individuals belonging to 44 families and 151 species have been found. The most common families regarding the amount of species were: Myrtaceae (28 species), Lauraceae (26), Aquifoliaceae (8) and Fabaceae (8), and Rubiaceae (6). Page 4 Tree Community in Cunha, São Paulo, Southeastern Brazil Picture 4. Bromeliads covering the soil of the “S” portion. (Photo: Gabriel Sabino) Both researches were conducted at an average altitude of 1,200 meters, but these areas can be considered as cloud forests (picture 5), with species which are typical of colder regions. Families such as Aquifoliaceae, Cunnoniaceae, Symplocaceae and Winteraceae are common in these formations and stand out due to the plenty and/or abundance of individuals. Many genera strongly correlated to high altitudes in Southeastern Brazil, such as Clethra, Clusia, Drimys, Ilex, Hedyosmum, Meliosma, Miconia, Myrsine, Podocarpus, Prunus, Roupala and Weinmannia, are also considered as diagnostic of Neotropic6 Cloud Forests. Picture 5. Inner part of the Cloud Atlantic Forest in the Itatiaia National Park. (Photo: Gabriel Sabino) Page 5 Tree Community in Cunha, São Paulo, Southeastern Brazil Glossary 1 – Phytosociology: Branch of plant science which deals with plant communities, the relationships between the species within them and with the environment. Explanatory text regarding phytosociology (in Portuguese): http://www.rc.unesp.br/biosferas/Art0065.html; 2 – Stipe: Nonbranching, usually straight and roughly cylindrical stem, with leaves located only on the top. Term used as a reference to palm tree stems; 3 – Understory: Plant life growing beneath the forest canopy; 4 – Cloud forests: Ombrophilous forests exhibit high precipitation levels. Cloud forests are usually located at an altitude over 1,500 meters; 5 – Montane forests: Forests located at an altitude between 500 and 1,500 meters; 6 – Neotropic ecozone: Ecozone including areas of Southern Mexico and California, Central America, all of the Caribbean islands and South America. Team: Ana Claudia Souza, Carlos Alfredo Joly, Gabriel Marcusso, Gabriel Pavan Sabino, Luis Bernacci, Renato Belinelo, Rodrigo Morais, Roberta Grillo, Marco A. Assis, Matheus Armelin Nogueira, Vitor de Andrade Kamimura. Page 6 .