Serving the state of São Paulo, the Tietê river in the Atlantic Biome is a powerhouse, yet it’s one of the most polluted rivers in Brazil. WeForest and AES Brasil are collaborating to restore the forest on the edges of the Tietê river and its tributaries with native species, protecting water bodies from soil siltation and runoff from herbicides and pesticides. The project is also providing a testing ground for pioneering restoration approaches that aim to reduce the use of herbicides – which are usually relied on in Brazil to control invasive grasses – or even eliminate them entirely.
Brazilian energy company AES Brasil is already carrying out forest restoration in areas where it is mandatory under law. AES Brasil will finance part of the project, develop the restoration methodology in conjunction with WeForest, and facilitate the monitoring of the restoration through satellite images.
CEIBA Consultoria Ambiental, a São Paulo State-based company specialized in the restoration of forest ecosystems, will be carrying out the restoration and maintenance activities without the use of herbicides or insecticides.
Protect water resources and improve the water supply for local communities, transitioning the region away from the use of herbicides that can have long-term damaging effects on biodiversity, water bodies and humans.
Increase forest cover by restoring riparian (riverbank) forests, establishing wildlife corridors to boost biodiversity.
Scale up from four to around 15 municipalities over time. The first phase aims to restore 2000 hectares on AES Tietê landholdings (representing around 4 000 000 trees). The total landscape at this side of the Tietê watershed could eventually encompass around 15 municipalities.
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Why is intervention needed?
Brazil’s Atlantic Forest stretches along the Atlantic coast and inland as far as Paraguay. It is thought to have covered as much as 1 500 000 km2, but today at least 72% has been cleared, mainly for agriculture. Most of the remaining forest patches are small and isolated, and many plant and animal species are threatened with extinction. Alongside the Tietê river, significant deforestation has taken place.
The Brazilian Forest Code aims to protect rivers, soils and forests on private lands. Unfortunately, the code is not always adhered to, often because of a lack of financial and technical capacity. Today, the land that officially falls under this law and that is not forested – in other words, that needs to be restored – amounts to around 19 million hectares.
Establishing wildlife corridors
AES Brasil is already restoring sites that the Brazilian Forest Code requires to be placed under restoration. The Tietê Forests project will focus on additional sites where this is not obligatory by law, actively planting native vegetation, enhancing a wildlife corridor and helping protect the river basin from erosion.
The region supports more than 100 mammal species, including the puma (Puma concolor) and the maned wolf (Chrysocyon brachyurus), of which 6 are threatened. It’s also home to over 400 bird species, of which 18 are threatened, more than 40 amphibian species, and several endangered or vulnerable tree species.
A fully green approach
In Brazil, invasive grasses and leaf-cutter ants are two major obstacles to forest restoration, and they are usually controlled with herbicides and insecticides. While it is possible to control them with a fully organic approach, it is extremely laborious and difficult to do on a large scale. With its aim to protect the water resources of one the largest rivers in the state of São Paulo, the Tietê Forests project serves as the perfect opportunity to experiment with ways to reduce or eliminate the use of herbicides and pesticides by testing different spatial arrangements or species combinations, and developing best practices.
To do this, the project adopts a three-pronged approach:
- The removal of grass prior to planting will be carried out mechanically by mowing.
- Green manure – Guandu or pigeonpea (Cajanus cajan) – will be used in between native vegetation as an extra contribution to the fast-growing and large-crowned plants that shade and suppress invasive grasses, accelerating the growth of all native species.
- The biomass of both the mown grass and the green manure will be used as mulch during tree planting, also to stop invasive grasses growing again.
* Carbon calculation methodology
The estimated carbon sequestration potential is 373tCO2/ha over 30 years.