Aspectos ecológicos e silviculturais de espécies florestais: subsídios a restauração florestal da Amazônia

Abstract

The combination of financial and ecological benefits in tropical forest restoration strategies is an alternative to reduce costs and provide economic returns to rural landowners who take on the responsibility of conserving biodiversity. We present integrated studies with the objective of subsidizing the restoration of degraded areas in the Amazon. In the first two studies we investigated four reforestation areas after 17 years of implantation in the northwest of Mato Grosso, at Fazenda São Nicolau (FSN) - headquarters of the Peugeot ONF Forest Carbon Well. The areas vary in arrangement, composition, use and proportion of Tectona grandis. We evaluated reforestation characteristics (implanted and regenerated species, diameter (D) and height (HT)) in 46 plots of 1000m2 and that were used in both surveys. In the first study we evaluated how silvicultural decisions affect the patterns of richness and similarity of natural regeneration and found that: i) the initial richness and composition of the planting modulate the colonization of new species; ii) the exotic species negatively affected recruitment, when in high proportions; iii) the greater spacing compensated the negative effect of the high amount of the exotic; iiii) dissimilarity among the areas associated with the characteristics analyzed. . In the second work, we investigated how decisions related to restoration planning can influence carbon accumulation and species gain, and also evaluate the optimum points of maximum mutual reach. For this we used the variables carbon stock of the tree component and regeneration species gain for our analyzes and inferences. We found that the use of the exotic and the increase of its proportion increase the carbon stock, however presenting an inverse effect on the increase of species. The planting spacing influenced our results, where densified sites presented higher carbon stock and lower gain, while the spacing increased resulted in a decrease in storage and higher gain. The last study was also carried out at the FSN, in which we evaluated the effectiveness in the establishment and occupation, evaluating the number of individuals (NI), intensity of sprouting (IP), Wood Above Biomass Ground (AGB), Cup Area D and HT by individuals from three strategies of forest restoration of riparian forests after 2.5 years of implantation. We evaluated 58 sample units (300m2) distributed among the Strategies in Total Area (PTA), Diversity Islands (ID) and Direct Seeding (DS) strategies. We also evaluated the main species in each strategy and their similarities. SD was highlighted in most of the analyzed variables (NI, AGB and AC) and thus we bet on it as promising, while the IP characteristic was higher in the ID and there were no differences in the mean D and HT. Each strategy presented a particular set of more successful species. Species have played an important role in differentiating strategies by providing distinct ecological functions that can influence ecological processes. Thus, silvicultural planning must focus on the formulation of public policies, since decisions can condition success and compromise the reach of biodiversity conservation and the economic benefits of forest restoration.