Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each fa...Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.展开更多
Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this p...Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change.展开更多
As the main body of Qinghai-Tibetan Plateau, North Tibet Plateau is one of three major sandy desertification regions in China and also a representative sandy desertification zone of Qinghai-Tibet Plateau. Accordingly,...As the main body of Qinghai-Tibetan Plateau, North Tibet Plateau is one of three major sandy desertification regions in China and also a representative sandy desertification zone of Qinghai-Tibet Plateau. Accordingly, it is an important region for the study of recent sandy desertification processes and formation mechanism. From such aspects as desertified land types, areas and distributions etc., this paper analyses in detail the sandy desertification status on North Tibet Plateau, and qualitatively and quantitatively deals with the main factors that affect recent sandy desertification processes and the driving mechanism. Research results show that North Tibet Plateau is an important sandy desertification region in China characterized with large desertified land areas, diversified types, high severity, extensive distributions and serious damages. Sandy desertification occurrence and development resulted from combined effects of natural factors, anthropogenic factors, natural processes and man-made processes, of which climatic change is the main driving force.展开更多
The reserve of soil nutrients is limited. In case of irrational use of land, nutrients would be depleted sooner. Before the 1950s the low grain production in China was maintained only by expanding the cultivated area ...The reserve of soil nutrients is limited. In case of irrational use of land, nutrients would be depleted sooner. Before the 1950s the low grain production in China was maintained only by expanding the cultivated area and by recycling of nutrients in agriculture. Calculation of nutrients balance showed that in the year of 1949 there were great deficits of N, P and K elements in agriculture of China. It revealed that there would have really been danger of soil nutrients exhaustion if such a situation had continued. Things have changed since the beginning of 1950s. The nutrients balance in agriculture has been getting better and better. In the year 1987 N and P balance got rid of their great deficits. But for K the deficit grew even larger. This resulted in a rapid expansion of soil area deficient in K in China since the mid 1970s. In spite of the fact that the P balance in the arable land of the whole country was positive, the field which did not receive P fertilizer had become deficient in P. So the area deficient in P also increased. It is stressed that great attention should be paid to the depletion of soil nutrients, especially K in the northern part of China where the soil is relatively rich in K. Of course, soil sulfur and microelements should be considered next.展开更多
Reforestation is an activity that involves planting or man-made trees regeneration and other plants in the state forest areas and in other areas based on land-use plan designated as forest. The purpose of this study w...Reforestation is an activity that involves planting or man-made trees regeneration and other plants in the state forest areas and in other areas based on land-use plan designated as forest. The purpose of this study was to determine the public perception of the difficulty of successful reforestation activities in the Lake Toba catchment area. The data were taken from primary and secondary data. Primary data were information collected by reforestation activities in the villages, secondary data were collected in the study site general conditions existing at the village government agencies, of which sampling method was done by purposive sampling, i.e., sampling deliberately chosen. The results showed a lack of socialization in the extension of government reforestation activities, uncontrolled forest fires, lack of maintenance of seed that has been planted, and the type of plant is less suitable.展开更多
It is important to study the contributions of climate change and human activities to cropland changes in the fields of both climate change and land use change. Relationships between cropland changes and driving forces...It is important to study the contributions of climate change and human activities to cropland changes in the fields of both climate change and land use change. Relationships between cropland changes and driving forces were qualitatively studied in most of the previous researches. However, the quantitative assessments of the contributions of climate change and human activities to cropland changes are needed to be explored for a better understanding of the dynamics of land use changes. We systematically reviewed the methods of identifying the contributions of climate change and human activities to cropland changes at quantitative aspects, including model analysis, mathematical statistical method, framework analysis, index assessment and difference comparison. Progress of the previous researches on quantitative evaluation of the contributions was introduced. Then we discussed four defects in the assessment of the contributions of climate change and human activities. For example, the methods were lack of comprehensiveness, and the data need to be more accurate and abundant. In addition, the scale was single and the explanations were biased. Moreover, we concluded a clue about quantitative approach to assess the contributions from synthetically aspect to specific driving forces. Finally, the solutions of the future researches on data, scale and explanation were proposed.展开更多
基金Under the auspices of Mexican National Council for Science and Technology (No 2008-01-87972)
文摘Forest fire is one of the major causes of forest loss and therefore one of the main constraints for sustainable forest management worldwide.Identifying the driving factors and understanding the contribution of each factor are essential for the management of forest fire occurrence.The objective of this study is to identify variables that are spatially related to the occurrence and incidence of the forest fire in the State of Durango,Mexico.For this purpose,data from forest fire records for a five-year period were analyzed.The spatial correlations between forest fire occurrence and intensity of land use,susceptibility of vegetation,temperature,precipitation and slope were tested by Geographically Weighted Regression(GWR) method,under an Ordinary Least Square estimator.Results show that the spatial pattern of the forest fire in the study area is closely correlated with the intensity of land use,and land use change is one of the main explanatory variables.In addition,vegetation type and precipitation are also the main driving factors.The fitting model indicates obvious link between the variables.Forest fire was found to be the consequence of a particular combination of the environmental factors,and when these factors coexist with human activities,there is high probability of forest fire occurrence.Mandatory regulation of human activities is a key strategy for forest fire prevention.
基金Under the auspices of the Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-341)National Natural Science Foundation of China (No. 40871187, 40801208)
文摘Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change.
文摘As the main body of Qinghai-Tibetan Plateau, North Tibet Plateau is one of three major sandy desertification regions in China and also a representative sandy desertification zone of Qinghai-Tibet Plateau. Accordingly, it is an important region for the study of recent sandy desertification processes and formation mechanism. From such aspects as desertified land types, areas and distributions etc., this paper analyses in detail the sandy desertification status on North Tibet Plateau, and qualitatively and quantitatively deals with the main factors that affect recent sandy desertification processes and the driving mechanism. Research results show that North Tibet Plateau is an important sandy desertification region in China characterized with large desertified land areas, diversified types, high severity, extensive distributions and serious damages. Sandy desertification occurrence and development resulted from combined effects of natural factors, anthropogenic factors, natural processes and man-made processes, of which climatic change is the main driving force.
文摘The reserve of soil nutrients is limited. In case of irrational use of land, nutrients would be depleted sooner. Before the 1950s the low grain production in China was maintained only by expanding the cultivated area and by recycling of nutrients in agriculture. Calculation of nutrients balance showed that in the year of 1949 there were great deficits of N, P and K elements in agriculture of China. It revealed that there would have really been danger of soil nutrients exhaustion if such a situation had continued. Things have changed since the beginning of 1950s. The nutrients balance in agriculture has been getting better and better. In the year 1987 N and P balance got rid of their great deficits. But for K the deficit grew even larger. This resulted in a rapid expansion of soil area deficient in K in China since the mid 1970s. In spite of the fact that the P balance in the arable land of the whole country was positive, the field which did not receive P fertilizer had become deficient in P. So the area deficient in P also increased. It is stressed that great attention should be paid to the depletion of soil nutrients, especially K in the northern part of China where the soil is relatively rich in K. Of course, soil sulfur and microelements should be considered next.
文摘Reforestation is an activity that involves planting or man-made trees regeneration and other plants in the state forest areas and in other areas based on land-use plan designated as forest. The purpose of this study was to determine the public perception of the difficulty of successful reforestation activities in the Lake Toba catchment area. The data were taken from primary and secondary data. Primary data were information collected by reforestation activities in the villages, secondary data were collected in the study site general conditions existing at the village government agencies, of which sampling method was done by purposive sampling, i.e., sampling deliberately chosen. The results showed a lack of socialization in the extension of government reforestation activities, uncontrolled forest fires, lack of maintenance of seed that has been planted, and the type of plant is less suitable.
基金National Natural Science Foundation of China,No.41401113,No.41371002,No.41471091The Science and Technology Strategic Pilot of the Chinese Academy of Sciences,No.XDA05090310The Key Project of Physical Geography of Hebei Province
文摘It is important to study the contributions of climate change and human activities to cropland changes in the fields of both climate change and land use change. Relationships between cropland changes and driving forces were qualitatively studied in most of the previous researches. However, the quantitative assessments of the contributions of climate change and human activities to cropland changes are needed to be explored for a better understanding of the dynamics of land use changes. We systematically reviewed the methods of identifying the contributions of climate change and human activities to cropland changes at quantitative aspects, including model analysis, mathematical statistical method, framework analysis, index assessment and difference comparison. Progress of the previous researches on quantitative evaluation of the contributions was introduced. Then we discussed four defects in the assessment of the contributions of climate change and human activities. For example, the methods were lack of comprehensiveness, and the data need to be more accurate and abundant. In addition, the scale was single and the explanations were biased. Moreover, we concluded a clue about quantitative approach to assess the contributions from synthetically aspect to specific driving forces. Finally, the solutions of the future researches on data, scale and explanation were proposed.