Forests slated to be legally cut down to build roads or hydroelectric power plants could be a source of material for enriching other forests being restored or for new forest formation. Researchers at the Forest Restoration and Ecology Laboratory of the Luiz de Queiroz School of Agriculture at the University of São Paulo (Esalq-USP) in Piracicaba have found that it is actually possible to transplant herbaceous plants, palm trees, climbing plants, bromeliads and orchids from a forest scheduled to be cleared, to other forests that are in the process of formation. Estimates indicate that this material—tiny seedlings, or plantules, of trees and shrubs, and seed-rich topsoil that are generally not utilized—accounts for 50% of a forest’s biological diversity. Now, it appears, such material can be used to supplement the planting of tree and shrub seedlings.
Just one hectare of mature forest could yield 80,000 to 190,000 tree seedlings before it is cut down. USP researchers estimate that this material could be used to replant more than 40 hectares. Other plants that could be removed from forests about to be cleared include epiphytes (orchids and bromeliads) and climbing plants that help reestablish interaction between plants, animals and the soil in forests into which they are introduced. Shrubs, herbaceous plants, palm trees, bromeliads and orchids introduced into forests in the process of restoration make them more diversified, colorful and flowery than forests that contain only trees.
If just some of the plantules in the 590 hectares that were legally deforested in 2009-2010 in the state of São Paulo had been collected, at least 23,000 hectares of new forests could have been replanted, according to calculations by the USP team coordinated by Sergius Gandolfi. If the seed-rich layer of topsoil had also been removed from the deforested area and then spread in degraded areas, more than 3,000 hectares could have been restored.
“Government regulatory agencies could incentivize the use of materials from legally deforested areas by establishing laws and encouraging those in charge to donate and receive this material,” Gandolfi says. He points out that incentives could also be offered to remove seedlings of native trees that grow spontaneously in eucalyptus plantations and are destroyed every six years when the eucalyptus trees are cut down and replanted. “Forestry companies could collect and donate this material to small farmers or even authorize the government, nursery operators or cooperatives to collect it free of charge,” he says.
In the field
The Esalq researchers propose three methods for reusing seeds, seedlings and epiphytes from a forest slated for clearing. The first method would be to remove a 30-centimeter layer of topsoil containing seeds, roots and germinating buds from the area to be deforested. The topsoil can be transferred and spread to form a six-centimeter layer in the desired reforestation or enrichment area.
The second method consists of removing seedlings from areas to be deforested. The plants are prepared by removing the soil and leaving the bare root, and are then transferred to a container with water, brought to a nursery and immediately replanted in plastic bags or tubes. In 2008, Cristina Yuri Vidal, a member of Gandolfi’s team, demonstrated the ecological, technical and economic viability of this approach when she transferred 2,106 seedlings (1-30 centimeters high) of trees, shrubs, lianas (climbing plants) and herbaceous species in a forested area slated to be cut down in Registro, in southern São Paulo State. Of the 98 species she collected, half were not being cultivated in nurseries and three were at risk of extinction. After seven months in nurseries, 60% of the plantules had survived.
In a more comprehensive study completed in 2011, her colleague Milene Bianchi dos Santos collected 43,000 plantules of 97 species of trees, lianas and herbaceous species from a forest set to be cut down in the municipality of Guará in São Paulo State, and cultivated them in a nursery. Subsequently, 400 seedlings of 20 species were planted in an area being restored and showed a survival rate of 91% after one year. “The above-90% survival rate obtained in this study demonstrates the viability of introducing species by producing seedlings from plantules collected in forests that are slated to be legally cleared,” she says.
Another method, which has now been proven viable, is to transplant epiphytes. In an experiment completed in November 2012, biologist Marina Duarte from Gandolfi’s team collected 360 specimens from six species of orchids, bromeliads and cactus and used sisal twine to attach them to trees in two forests undergoing restoration in inland São Paulo State—a 13-year-old forest in Santa Bárbara d’Oeste and a 23-year-old forest in Iracemápolis.
After one year observing the plants, Duarte concluded that epiphytes can be viably transplanted, particularly when it is early in the rainy season. She also found that when the transplants are reinforced with palm tree fiber, the survival rate of the epiphytes ranged from 63% to 100% in the 13-year-old forest, and 55% to 90% in the other forest. “Even when they don’t survive for long,” she observed,” epiphytes help enrich the environments into which they are introduced.”
Transferring plantules, direct seeding and planting native understory species to enrich degraded forest areas undergoing restoration (2008/56588-8); Grant mechanism Regular Line of Research Project Award; Coord. Sergius Gandolfi/Esalq/USP; Investment R$19,770.03 (FAPESP).