Forest fire history can be reconstructed over past centuries across a wide variety of forest types. Fire scars on living tress, and age classes of forest stands, are the two sources of information for these reconstruc...Forest fire history can be reconstructed over past centuries across a wide variety of forest types. Fire scars on living tress, and age classes of forest stands, are the two sources of information for these reconstructions. Point and area frequencies are used to reconstruct fire history. Point frequencies are useful in forest types that burn with frequent, low intensity fire so that many fire-scarred residual trees exist. A true point is a single tree, but more often point estimates are made by combining fire scar records from several adjacent trees. Area frequences are applied where fires are infrequent but of moderate to high intensity, so that stand ages are used across wide areas to estimate fire return interals. Proper selection and application of fire history methods are essential to deriving useful ecological implications from fire history studies.This review evaluates the common methods of determining fire history :what the techniques are, where they are best applied, and how to interpret them in an ecological context. Emphasis is placed on fire freqency and predictability, but choosing a proper technique may also be a function of fire intensity.展开更多
Recent fire statistics and preliminary fire history data suggest that fire has been historically responsible for maintaining the vegetative communities up to present in Daxinganling region. Forest types, and even tree...Recent fire statistics and preliminary fire history data suggest that fire has been historically responsible for maintaining the vegetative communities up to present in Daxinganling region. Forest types, and even tree species, arc dependent on the degree of fire intensity, fire size, depth of burn and fire frequency. Selected samples of larch, pine, birch and spruce forest were studied in terms of species composition as determined by fire frequency which mainly depends on topography and site conditions. Intervals between fires range between 6 and 170 years.展开更多
A Late Pleistocene-Holocene pollen, phosphorus, and charcoal record was reconstructed from a peatland in southern Jiangxi Province in southern China. The area today has a mountainous and rolling landscape with village...A Late Pleistocene-Holocene pollen, phosphorus, and charcoal record was reconstructed from a peatland in southern Jiangxi Province in southern China. The area today has a mountainous and rolling landscape with villages, small towns, and agriculture dominated by rice paddies, vegetable, and fruit gardens, as well as areas of secondary forest and pine re-afforestation. The record opens before 14 300 yr BP, with Alnus woodland dominating the wetland areas and with an open Quercus woodland on the surrounding slopes. The forest area becomes more complex from approximately 12 800 yr BP and further from 9 000 yr BP. At approximately 6 000 yr BP, there is evidence of clearing and, by 4 500-4 000 yr BP, a complete collapse in the wetland Alnus and terrestrial forest as the low-lying areas are converted to rice production. For much of the record, the occurrence of fire around the site was low, although there is evidence of regional fires. Fire was used as a tool in clearing and then used in the annual cycles of stubble burning after rice harvest. Nutrient levels, as reflected by total phosphorus in the sediment, seem to be closely related to forest changes and high values in the surface layers probably result from land-management techniques associated with agriculture. Therefore, human impact greatly altered forest cover, fire frequency, and nutrient dynamics; this has been evident for approximately 6 000 yr BP and then intensities towards the present day.展开更多
文摘Forest fire history can be reconstructed over past centuries across a wide variety of forest types. Fire scars on living tress, and age classes of forest stands, are the two sources of information for these reconstructions. Point and area frequencies are used to reconstruct fire history. Point frequencies are useful in forest types that burn with frequent, low intensity fire so that many fire-scarred residual trees exist. A true point is a single tree, but more often point estimates are made by combining fire scar records from several adjacent trees. Area frequences are applied where fires are infrequent but of moderate to high intensity, so that stand ages are used across wide areas to estimate fire return interals. Proper selection and application of fire history methods are essential to deriving useful ecological implications from fire history studies.This review evaluates the common methods of determining fire history :what the techniques are, where they are best applied, and how to interpret them in an ecological context. Emphasis is placed on fire freqency and predictability, but choosing a proper technique may also be a function of fire intensity.
文摘Recent fire statistics and preliminary fire history data suggest that fire has been historically responsible for maintaining the vegetative communities up to present in Daxinganling region. Forest types, and even tree species, arc dependent on the degree of fire intensity, fire size, depth of burn and fire frequency. Selected samples of larch, pine, birch and spruce forest were studied in terms of species composition as determined by fire frequency which mainly depends on topography and site conditions. Intervals between fires range between 6 and 170 years.
基金SuppoSed by funding from the Australia-China Co-operation and the National Natural Science Foundation of China （40372077）. Acknowledgements The authors thank Huabing Xie and Redao Xie for digging the pit from which the samples were taken, Lorraine Wilson for preparing the samples for pollen analysis, and Xue Shang and Xinying Zhou for help with the preparation of the diagrams.
文摘A Late Pleistocene-Holocene pollen, phosphorus, and charcoal record was reconstructed from a peatland in southern Jiangxi Province in southern China. The area today has a mountainous and rolling landscape with villages, small towns, and agriculture dominated by rice paddies, vegetable, and fruit gardens, as well as areas of secondary forest and pine re-afforestation. The record opens before 14 300 yr BP, with Alnus woodland dominating the wetland areas and with an open Quercus woodland on the surrounding slopes. The forest area becomes more complex from approximately 12 800 yr BP and further from 9 000 yr BP. At approximately 6 000 yr BP, there is evidence of clearing and, by 4 500-4 000 yr BP, a complete collapse in the wetland Alnus and terrestrial forest as the low-lying areas are converted to rice production. For much of the record, the occurrence of fire around the site was low, although there is evidence of regional fires. Fire was used as a tool in clearing and then used in the annual cycles of stubble burning after rice harvest. Nutrient levels, as reflected by total phosphorus in the sediment, seem to be closely related to forest changes and high values in the surface layers probably result from land-management techniques associated with agriculture. Therefore, human impact greatly altered forest cover, fire frequency, and nutrient dynamics; this has been evident for approximately 6 000 yr BP and then intensities towards the present day.
