Biomassa em vegetação de restauração florestal de dois anos na planície costeira em Caraguatatuba, SP

• Ano de defesa: 2017
• Autor(a) principal: Horikawa, Natacia Ery [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Allometry; Seedlings; Roo: shoot; Allocation; Allometric model; Alometria; Mudas; Root: shoot; Alocação; Modelo alométrico
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5021647; http://repositorio.unifesp.br/handle/11600/50011

Biomass is a fundamental parameter of functional characterization of ecosystems. It constitutes one of the main carbon reservoirs of terrestrial ecosystems, thus being a relevant in the context of mitigation of climate change. The objective of this study is to describe the biomass in mixed species coastal plain restoration planting in Caraguatatuba, SP. More specifically (i) Evaluate mortality and growth of the most abundant planting species; (ii) Develop allometric models to estimate total and aboveground biomass; (iii) Quantify the accumulated biomass in the first two years as well as the contribution of roots to the biomass budget; (iv) Evaluate how fertility and growth rate affect the relative biomass allocation (above and below ground). The study area of approximately 7 ha was previously covered by pasture. In 2012 were planted 15.690 seedlings of 48 species. The diameter at soil height (DAS), height (H) and canopy (COB) of 3.020 seedlings of 25 species planted in a row, alternating pioneer and non– pioneer species in plots with and without nutrient were measured in a semester basis. The relative growth rate (RGR) of all selected seedlings was calculated. To obtain the dry weight, 67 seedlings of 21 species were collected. Allometric models were then built using linear regression between dry weight and measured dimensions (DAS, H and COB). The effect of fertility and individual RGR on the relative biomass allocation were tested using mixed linear models. The models were selected using the Akaike Information Criteria. Initial mortality was high (> 20%). It was significantly reduced in the second year to 9%. Lower mortality and higher RGRs were recorded in Citharexylum myrianthum, while Euterpe edulis presented mortality > 90% and low RGRs. The best allometric models selected were: Ln(biomass) = -0.25 + 0.82 Ln(DAS² * H) (R² = 0.94, p <0.001) for the total biomass; and Ln(biomass) = -0.78 + 0.85 Ln(DAS² * H) (R² = 0.92, p <0.001) for the abovegroung biomass. The total biomass accumulated at the whole area was calculated as 50 Mg.ha-1 and the aboveground biomass about 35 Mg.ha-1. Roots represented 30% of the total biomass. The models indicated that the effect of fertility on the relative biomass allocation was uncertain. However, the RGR affected the relative biomass allocation. The R: S ratio decreased as the RGR becomes higher. In general, pioneer species had lower mortality and higher growth rates than non-pioneers. The results suggest caution when planting shade tolerant species in the initial stages of the restoration, with an alternative approach of later introduction of this kind of species in plantations. Fast-growing seedlings presented a preferential allocation in aboveground biomass, whereas the slow-growing seedlings had preference to belowground biomass, which is a clear indication of different strategies in the capture and use of resources. The models described the planting satisfactorily, providing accurate estimates of biomass. The results reinforce the importance of considering roots in biomass estimates and indicate high potential of mixed species restoration plantations in subtropical regions to mitigate the greenhouse effect.