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Abstract(s)
Os incêndios florestais causam imensos impactos sociais, econômicos e ambientais em Portugal, principalmente no nordeste do país. Uma das razões desta problemática é o abandono de propriedades em razão de suas características impróprias para mecanização e produção em massa. Deste modo, é de grande relevância o uso de práticas de gestão da vegetação para controle de material combustível em tais áreas, como o fogo controlado. Comumente utilizado na região mediterrânea, o fogo controlado constitui uma importante ferramenta de redução da quantidade de combustível disponível, sendo de baixo custo, rápido e contribui para a redução do risco de ocorrência de incêndios florestais. Esta técnica permuta as condições severas e intensas de um incêndio por condições mais amenas, de modo a impactar menos o ambiente. Porém, também realiza imensas modificações na paisagem e impacta diretamente a dinâmica do carbono na atmosfera. Neste contexto, este trabalho tem como principal objetivo avaliar a dinâmica temporal do armazenamento de carbono na sequência da aplicação de um fogo controlado numa área de matos do Parque Natural de Montesinho, nordeste de Portugal. Antes da aplicação do fogo, a área de estudo era constituída por vegetação arbustiva, essencialmente por urze (44%), esteva (26%) e carqueja (30%). A carqueja e a urze apresentaram um fator de combustão de 80%, enquanto a esteva revelou maior resistência ao fogo, com um fator de combustão de 50%. Então, em 11 locais distribuídos de forma aleatória, foi avaliado o carbono na biomassa aérea e radicular da vegetação arbustiva (urze, esteva e carqueja), no horizonte orgânico e no solo, através de colheitas de amostras nas profundidades 0-5, 5-10 e 10-20 cm, antes do fogo controlado, dois meses, seis meses e três anos após o fogo controlado. Os resultados mostram uma elevada redução do teor de carbono armazenado na biomassa da vegetação arbustiva e uma redução total do horizonte orgânico do solo após o fogo. Dois e seis meses após o fogo a área não apresentou horizonte orgânico. O carbono armazenado no solo mineral revelou um acréscimo de cerca de 6,4 t ha-1 no final do período considerado. Dentre as espécies arbustivas, a urze apresentou maior armazenamento de carbono, com cerca de 70% de carbono radicular. Dois meses após o fogo, a taxa anual de perda de carbono era de 43,5 t ha-1 ano-1 (7,4 t ha-1 em dois meses) contra 21,5 t ha-1 ano-1 após seis meses (10,8 t ha-1 em seis meses), apresentando um ganho de 0,24 t ha-1 ano-1 após três anos (0,7 t ha-1 em três anos) comparativamente à situação antes do fogo controlado. Assim, no final do período considerado a dinâmica de armazenamento de carbono no sistema foi recuperada, com maior influência do compartimento solo. Dentre os compartimentos analisados (biomassa aérea e radicular, horizonte O e solo), a maior quantidade de carbono está presente no solo.
The forest fires cause immense social, economic and environmental impacts in Portugal, mainly in the northeast of the country. One of the causes of this problem is the abandonment of properties because of their unfit characteristics for mechanization and mass production. Therefore, the use of vegetation management practices to control fuel material in such areas, such as controlled fire, is of great relevance. Commonly used in the Mediterranean region, controlled fire is an important tool for reducing the amount of fuel available and is of low cost, and contributes to reducing the risk of forest fires occurring. This technique interchanges the severe and intense conditions of a fire with cooler conditions, so as to have less impact on the environment. However, it also makes immense changes to the landscape and directly impacts the dynamics of carbon in the atmosphere. In this context, this work has as main objective to evaluate the temporal dynamics of carbon storage following the application of a controlled fire in an area of Montesinho Natural Park, northeast of Portugal. Before the application of the fire, the study area was covered by shrub vegetation, essentially by urze (44%), esteva (26%) and carqueja (30%). The carqueja and urze presented a combustion factor of 80%, while the esteva showed higher resistance to fire, with a combustion factor of 50%. Then, in 11 randomly distributed locations, carbon was evaluated in the aerial and root biomass of the shrub vegetation (urze, esteva and carqueja), in the organic horizon and in the soil, through sampling at depths 0-5, 5-10 and 10-20 cm, before the controlled fire, two months, six months and three years after the controlled fire. The results show a high reduction in the carbon content stored in the biomass of the shrub vegetation and a total reduction in the organic horizon of the soil after the fire. Two and six months after the fire the area showed no organic horizon. The carbon stored on the mineral soil showed an increase of about 6.4 t ha-1 at the end of the period considered. Among the shrub species, heather presented higher carbon storage, with about 70% root carbon. Two months after the fire, the annual carbon loss rate was 43.5 t ha-1 year-1 (7.4 t ha-1 in two months) versus 21.5 t ha-1 year-1 after six months (10.8 t ha-1 in six months), with a gain of 0.24 t ha-1 year after three years (0.7 t ha-1 in three years) compared to the situation before the controlled fire. Thus, at the end of the period considered the carbon storage dynamics in the system was recovered, with greater influence of the soil compartment. Among the compartments analyzed (aerial and root biomass, horizon O and soil), the greatest amount of carbon is present in the soil.
The forest fires cause immense social, economic and environmental impacts in Portugal, mainly in the northeast of the country. One of the causes of this problem is the abandonment of properties because of their unfit characteristics for mechanization and mass production. Therefore, the use of vegetation management practices to control fuel material in such areas, such as controlled fire, is of great relevance. Commonly used in the Mediterranean region, controlled fire is an important tool for reducing the amount of fuel available and is of low cost, and contributes to reducing the risk of forest fires occurring. This technique interchanges the severe and intense conditions of a fire with cooler conditions, so as to have less impact on the environment. However, it also makes immense changes to the landscape and directly impacts the dynamics of carbon in the atmosphere. In this context, this work has as main objective to evaluate the temporal dynamics of carbon storage following the application of a controlled fire in an area of Montesinho Natural Park, northeast of Portugal. Before the application of the fire, the study area was covered by shrub vegetation, essentially by urze (44%), esteva (26%) and carqueja (30%). The carqueja and urze presented a combustion factor of 80%, while the esteva showed higher resistance to fire, with a combustion factor of 50%. Then, in 11 randomly distributed locations, carbon was evaluated in the aerial and root biomass of the shrub vegetation (urze, esteva and carqueja), in the organic horizon and in the soil, through sampling at depths 0-5, 5-10 and 10-20 cm, before the controlled fire, two months, six months and three years after the controlled fire. The results show a high reduction in the carbon content stored in the biomass of the shrub vegetation and a total reduction in the organic horizon of the soil after the fire. Two and six months after the fire the area showed no organic horizon. The carbon stored on the mineral soil showed an increase of about 6.4 t ha-1 at the end of the period considered. Among the shrub species, heather presented higher carbon storage, with about 70% root carbon. Two months after the fire, the annual carbon loss rate was 43.5 t ha-1 year-1 (7.4 t ha-1 in two months) versus 21.5 t ha-1 year-1 after six months (10.8 t ha-1 in six months), with a gain of 0.24 t ha-1 year after three years (0.7 t ha-1 in three years) compared to the situation before the controlled fire. Thus, at the end of the period considered the carbon storage dynamics in the system was recovered, with greater influence of the soil compartment. Among the compartments analyzed (aerial and root biomass, horizon O and soil), the greatest amount of carbon is present in the soil.
Description
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
Keywords
Parque Natural de Montesinho Incêndios florestais Montanha Vegetação arbustiva Carbono no sistema