Estimativa de sequestro de carbono florestal para restauração ecológica devido às emissões de CO2 na instalação de uma central geradora hidrelétrica - CGH
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Data
2017-06-26
Autores
Castro, Alcinéa Guimarães de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
São inúmeros os serviços econômicos, sociais e ambientais atribuídos às florestas, sendo a fixação do carbono atmosférico o mais recente, pois contribui para a redução de gases do efeito estufa (GEE) e do aquecimento global, através do processo de fotossíntese na absorção do dióxido de carbono (CO2) pelas árvores. Buscando a redução dos GEE e a absorção do CO2, as centrais geradoras hidrelétricas (CGHs) e as pequenas centrais hidrelétricas (PCHs) são consideradas, por muitos estudiosos, como uma forma mais limpa de obtenção de energia, ainda que existam algumas discussões sobre os impactos ambientais gerados pelas mesmas. Assim, este estudo visa propor a mitigação da emissão do CO2, por meio da restauração ecológica, devido à instalação de uma central geradora hidrelétrica, com base na análise do potencial dos remanescentes florestais como sumidouros de carbono. Desta forma, utilizou-se mapas georreferenciados com dados físicos ambientais (hidrologia, classe de solo, uso da terra, drenagem, área de preservação permanente e maciços florestais nativos) que possibilitaram delimitar os remanescentes florestais existentes na bacia hidrográfica do Rio do Chapéu, localizada no município de São Luís do Paraitinga, SP, Brasil. Paralelamente, levantou-se os dados dendrométricos (altura da árvore e diâmetro à altura do peito) de 658 indivíduos arbóreos, distribuídos em 119 espécies de um fragmento florestal de 10.000 m2, que foram aplicados em equações alométricas, resultando uma estimativa de 62,25 t C ha-1 fixados pelas árvores e uma emissão de 9.232,92 t CO2 ha-1 devido à área de floresta inundada (reservatório) com a implantação de uma CGH hipotética na bacia hidrográfica. Esses dados evidenciaram que os componentes arbóreos contribuem para a fixação do carbono e que há necessidade da compensação ambiental, por meio da restauração ecológica, em 323,8 hectares de áreas de preservação permanente localizadas na bacia hidrográfica de contribuição. Considerando que atualmente não existem modelos para se estimar as GEE antes da construção do reservatório e que no Brasil a maior parte da energia elétrica gerada advém de usinas hidrelétricas, esta pesquisa poderá contribuir com o processo de licenciamento ambiental e na tomada de decisão quanto à implantação de centrais hidrelétricas, obtendo parâmetros e formas seguras de compensação ambiental, aos efeitos negativos gerados pelas emissões de GEE, em especial o CO2.
There are numerous economic, social and environmental services to forests, among which atmospheric carbon sequestration is the most recent, which contributes to reducing greenhouse gas (GHG) emissions and global warming through photosynthesis, i.e. carbon dioxide (CO2) absorption by trees. With the aim of reducing greenhouse gas emissions and absorbing CO2, small hydropower stations (SHS) and small hydropower plants (SHPs) are considered as a cleaner way to generate energy in literature, although there is some discussion regarding their environmental impacts. Thus, the present study aims to mitigate CO2 emissions from building a hydropower station through ecological restoration based on analyzing the potential of utilizing remnant forests as carbon sinks. Therefore, georeferenced maps have been used with environmental physical data (hydrology, soil type, land use, drainage, permanent preservation areas and native forest) that allowed defining the existing remnant forests along the Chapéu River watershed, which is located in São Luís do Paraitinga, SP, Brazil. In addition, dendrometric data (height and diameter at breast height) has been collected on 658 individual trees classified into 119 species in a forest area of 10,000 m2. Data used in an allometric equation resulted in an estimate of 62.25 C ha-1 t sequestrated by trees and CO2 emission of 9232.92 t ha-1 due to the flooded forest area (dam) if a SHS were constructed in the watershed. These data evidenced that trees contribute to carbon sequestration, and that there must be an environmental compensation through ecological restoration of 323.8 hectares of permanent environmental reserve areas located in the contributing watersheds. This research is going to assist in environmental licensing and decision-making processes regarding the implementation of hydropower stations due to obtaining parameters and safe forms of environmental compensation for the negative impacts generated by greenhouse gas emissions, especially CO2, given that there are currently no GHG estimation models before the dam implementation and most of the electricity supply is generated by hydropower plants in Brazil.
There are numerous economic, social and environmental services to forests, among which atmospheric carbon sequestration is the most recent, which contributes to reducing greenhouse gas (GHG) emissions and global warming through photosynthesis, i.e. carbon dioxide (CO2) absorption by trees. With the aim of reducing greenhouse gas emissions and absorbing CO2, small hydropower stations (SHS) and small hydropower plants (SHPs) are considered as a cleaner way to generate energy in literature, although there is some discussion regarding their environmental impacts. Thus, the present study aims to mitigate CO2 emissions from building a hydropower station through ecological restoration based on analyzing the potential of utilizing remnant forests as carbon sinks. Therefore, georeferenced maps have been used with environmental physical data (hydrology, soil type, land use, drainage, permanent preservation areas and native forest) that allowed defining the existing remnant forests along the Chapéu River watershed, which is located in São Luís do Paraitinga, SP, Brazil. In addition, dendrometric data (height and diameter at breast height) has been collected on 658 individual trees classified into 119 species in a forest area of 10,000 m2. Data used in an allometric equation resulted in an estimate of 62.25 C ha-1 t sequestrated by trees and CO2 emission of 9232.92 t ha-1 due to the flooded forest area (dam) if a SHS were constructed in the watershed. These data evidenced that trees contribute to carbon sequestration, and that there must be an environmental compensation through ecological restoration of 323.8 hectares of permanent environmental reserve areas located in the contributing watersheds. This research is going to assist in environmental licensing and decision-making processes regarding the implementation of hydropower stations due to obtaining parameters and safe forms of environmental compensation for the negative impacts generated by greenhouse gas emissions, especially CO2, given that there are currently no GHG estimation models before the dam implementation and most of the electricity supply is generated by hydropower plants in Brazil.
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Palavras-chave
Centrais hidrelétricas, Captura de CO2, Restauração ecológica, Compensação ambiental, Bacias hidrográficas, CO2 Capture, Hydropower plants, Restoration ecological, Environmental compensation, Watersheds