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Abstract(s)
Atualmente os fogos florestais constituem um grave problema nos ecossistemas mediterrâneos. O abandono das áreas rurais originou a acumulação de biomassa combustível. Uma das técnicas aplicadas na gestão da vegetação em espaços florestais é o fogo controlado, que visa reduzir a carga combustível garantindo uma diminuição do perigo de incêndio. A sua aplicação em áreas estratégicas pretende substituir de uma forma gradual os incêndios que ocorrem durante o período estival por queimas pouco intensas realizadas no Inverno.
O fogo reduz ou elimina temporariamente a cobertura vegetal do solo e diversas alterações podem ocorrer nas propriedades físicas, químicas, mineralógicas e biológicas do solo.
Este trabalho tem como objetivo avaliar a evolução temporal do efeito do fogo controlado de baixa severidade em áreas de montanha cobertas com mato, em algumas propriedades do solo.
O estudo decorreu em Aveleda, dentro da área do Parque Natural de Montesinho, que possui uma superfície de cerca de 75000 ha, estando aproximadamente um terço ocupada por matos. A amostragem realizou-se numa área com cerca de 5 ha, ocupada por matos, que foi sujeita a fogo controlado. Em onze locais diferentes, distribuídos aleatoriamente foram colhidas amostras de solo antes do fogo controlado a diferentes profundidades: 0-5 cm, 5-10 cm e 10-20 cm. Para acompanhar a evolução das propriedades no tempo, foram colhidas novamente amostras de solo nos mesmos locais, dois meses, seis meses e três anos após o fogo controlado.
Na profundidade 0-5 cm, três anos após o fogo controlado, verifica-se que os valores de pH e o teor em Na+ do solo se apresentam semelhantes aos observados antes do fogo, o mesmo não se verifica com os valores da acidez de troca, alumínio de troca e o grau de saturação em bases (GSB) que diferem significativamente dos observados antes do fogo. Também se verifica que o fogo controlado, afeta as propriedades químicas de forma diferente ao longo do perfil do solo.
Currently, forest fires are a serious problem in the Mediterranean ecosystems. The abandonment of the rural areas has led to the accumulation of biomass fuel. One of the techniques applied in the management of vegetation in forest areas is the controlled fire, which aims to reduce the combustible load guaranteeing a reduction of the risk of fire. Its application in strategic areas intends to gradually replace the fires that occur during the summer period for less intense burnings carried through winter. The fire temporarily reduces or eliminates the vegetal covering of the ground and several alterations may occur in the physical, chemical, mineralogical and biological properties of the soil. This work aims to evaluate the temporal evolution of the effect of controlled low severity fire in mountain areas covered with bushes in some of the soil´s properties The study took place in Aveleda, within the area of the Montesinho Natural Park, which possesses a surface of about 75000 ha, being approximately one-third occupied by bushes. Sampling took place in an area with approximately 5 ha, occupied by bushes, which was subjected to controlled fire. In eleven different locations, randomly scattered, soil samples were collected before the controlled fire at different depths: 0-5 cm, 5-10 cm and 10-20 cm. To monitor the development of the properties in time, soil samples were once again collected in the same places, two months, six months and three years after the controlled fire. Three years after the controlled fire, and at a depth of 0-5 cm, it turned out that the values of the pH and the Na+ of the soil were similar to those seen before the fire. However, the same was not verified with the values of the acidity of exchange, aluminium of exchange and the degree of saturation in bases that differ significantly from the observed ones before the fire. It also appears that the controlled fire, affects the chemical properties differently throughout the soil profile.
Currently, forest fires are a serious problem in the Mediterranean ecosystems. The abandonment of the rural areas has led to the accumulation of biomass fuel. One of the techniques applied in the management of vegetation in forest areas is the controlled fire, which aims to reduce the combustible load guaranteeing a reduction of the risk of fire. Its application in strategic areas intends to gradually replace the fires that occur during the summer period for less intense burnings carried through winter. The fire temporarily reduces or eliminates the vegetal covering of the ground and several alterations may occur in the physical, chemical, mineralogical and biological properties of the soil. This work aims to evaluate the temporal evolution of the effect of controlled low severity fire in mountain areas covered with bushes in some of the soil´s properties The study took place in Aveleda, within the area of the Montesinho Natural Park, which possesses a surface of about 75000 ha, being approximately one-third occupied by bushes. Sampling took place in an area with approximately 5 ha, occupied by bushes, which was subjected to controlled fire. In eleven different locations, randomly scattered, soil samples were collected before the controlled fire at different depths: 0-5 cm, 5-10 cm and 10-20 cm. To monitor the development of the properties in time, soil samples were once again collected in the same places, two months, six months and three years after the controlled fire. Three years after the controlled fire, and at a depth of 0-5 cm, it turned out that the values of the pH and the Na+ of the soil were similar to those seen before the fire. However, the same was not verified with the values of the acidity of exchange, aluminium of exchange and the degree of saturation in bases that differ significantly from the observed ones before the fire. It also appears that the controlled fire, affects the chemical properties differently throughout the soil profile.