Browsing by Subject "Atlantic forest"

The Atlantic forest on the Eastern coast of Brazil is one of the world’s most endangered biotopes. Less than 12 % of the original forest remains due to agricultural and pasture expansion. In addition, many Atlantic forest restoration projects in the past have failed, largely because of inadequate silvicultural practices. Meanwhile, the growth rates of Eucalyptus and pine plantations have been increased 3 to 4 fold in Brazil over the last four decades by utilizing intensive silvicultural methods such as site preparation, fertilization, and weed control which in turn increases resource supply (nutrient, water and light). This study determines the effects of these same intensive silvicultural methods on Atlantic forest restoration regarding initial growth and carbon sequestering. Two parallel research sites were established in 2004 on latitudes 11°S and 23°S on the Eastern coast of Brazil to determine the effects of intensive silviculture, planting density and species composition on the development of 20 native tree species. This research focused on the Northern site (200 km North of Salvador, Bahia State) which has a typical tropical climate and soil type. The project has a 23 factorial design totalling 8 treatments, with the following factors: i) intensive and traditional treatments; ii) initial planting densities (3333 trees ha-1 and 1667 trees ha-1); and iii) species composition proportion (50:50 and 67:33 ratio of pioneer vs. late successional species). After 8 years from planting, survival and development of each species, aboveground biomass and leaf area index (LAI) were determined for all the treatments to compare the effects of the different factors. In summary, the main findings of this study are: 1) The more intensive management methods improved survival and the initial growth of tree species 2) Lower stand density (1667 trees ha-1) had the best response to the intensive management for LAI, stemwood production, and above ground carbon sequestration 3) Out of 20 species, 19 had significantly higher growth with intensive management, indicating that both pioneer and late successional species are constrained by the original site conditions. 4) Intensive management was essential, especially for non-pioneer species. 5) Under low intensity silviculture, the 67:33 ratio pioneers vs. non-pioneers with higher planting density (3333 trees ha-1) was the best option to obtain the highest stemwood volumes 8 years from planting, while the 50:50 ratio pioneers vs. non-pioneers with lower planting density (1667 tree ha-1) could be recommended under intensive silviculture. Conclusion: Intensive management methods have the potential to increase early restoration success by increasing biodiversity through enchancing survival and growth of non-pioneer species and accelerating the canopy closure. Intensive management methods increased the above ground carbon sequestered in 8 years, remarkably, up to 3-fold compared to traditional management, making it an attractive management option for carbon offsets.