This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transfo...This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transformations to determine relevant nonlinear forest wildfire size functions.Data from the Prague-East District of the Czech Republic was used for model derivation.Individual burned forest area was hypothesized as a function of water vapor pressure,air temperature and wind speed.Wind speed was added to enhance predictions of the size of forest wildfires,and further improvements to the utility of prediction methods were added to the regression equation.The results show that if the air temperature increases,it may contain less water and the fuel will become drier.The size of the burned area then increases.If the relative humidity in the air increases and the wind speed decreases,the size of the burned area is reduced.Our model suggests that changes in the climate factors caused by ongoing climate change could cause significant changes in the size of wildfire in forests.展开更多
Based on the research of the Forest Burning Links published in the Journal of Northeast Forestry University in 1987, this paper continues to study the theory of forest burning. Fire behavior has been divided into two ...Based on the research of the Forest Burning Links published in the Journal of Northeast Forestry University in 1987, this paper continues to study the theory of forest burning. Fire behavior has been divided into two important series in this paper. One is fire occurrence and spread, and the other is burning intensity. The first series has been divided into three grades as A: to burn difficulty and spread slowly; B: to burn possibly and spread little fast; and C: to burn easily and spread fast. The second series has been divided into four grades as Ⅰ: light burning; Ⅱ: medium burning; Ⅲ: intense burning; and Ⅳ: severe burning. The first series can be put as ordinate, and the second series can be put as abscissa. Then the network of 12 forest burning links can be formed. In the network, the relationship, the law of distribution and the variation of different forest burning links can be shown clearly. The studies of the distribution of fuel types, topography, site and fire kinds in the network can provide the basic theory for fire management.展开更多
Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutri...Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutrients.The aim of this study was to determine the effect of burning accumulated forest residues(slash)on soil chemical properties and how trees respond.We analyzed 40 burned and unburned sites and compared growth of Eucalyptus grandis W.Hill ex Maiden between sites.Soil pH increased by 39%after fire,suggesting reduced soil acidity and increased liming.Total nitrogen increased by 100%;other nutrients(Ca^2+,Mg^2+and K^+)also increased.Increase in nutrients had a significant effect on the growth of E.grandis;larger and taller trees were associated more with burned than unburned sites.This study provides evidence that burning accumulated slash during land preparation prior to plantation establishment alters soil nutrient status and enhances the growth of E.grandis.展开更多
基金funded by grant"EVA4.0",No.CZ.02.1.01/0.0/0.0/16_019/0000803 financed by the Operational Program Research,Development and Education(OP RDE),the Ministry of Education of the Czech Republic。
文摘This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transformations to determine relevant nonlinear forest wildfire size functions.Data from the Prague-East District of the Czech Republic was used for model derivation.Individual burned forest area was hypothesized as a function of water vapor pressure,air temperature and wind speed.Wind speed was added to enhance predictions of the size of forest wildfires,and further improvements to the utility of prediction methods were added to the regression equation.The results show that if the air temperature increases,it may contain less water and the fuel will become drier.The size of the burned area then increases.If the relative humidity in the air increases and the wind speed decreases,the size of the burned area is reduced.Our model suggests that changes in the climate factors caused by ongoing climate change could cause significant changes in the size of wildfire in forests.
文摘Based on the research of the Forest Burning Links published in the Journal of Northeast Forestry University in 1987, this paper continues to study the theory of forest burning. Fire behavior has been divided into two important series in this paper. One is fire occurrence and spread, and the other is burning intensity. The first series has been divided into three grades as A: to burn difficulty and spread slowly; B: to burn possibly and spread little fast; and C: to burn easily and spread fast. The second series has been divided into four grades as Ⅰ: light burning; Ⅱ: medium burning; Ⅲ: intense burning; and Ⅳ: severe burning. The first series can be put as ordinate, and the second series can be put as abscissa. Then the network of 12 forest burning links can be formed. In the network, the relationship, the law of distribution and the variation of different forest burning links can be shown clearly. The studies of the distribution of fuel types, topography, site and fire kinds in the network can provide the basic theory for fire management.
文摘Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutrients.The aim of this study was to determine the effect of burning accumulated forest residues(slash)on soil chemical properties and how trees respond.We analyzed 40 burned and unburned sites and compared growth of Eucalyptus grandis W.Hill ex Maiden between sites.Soil pH increased by 39%after fire,suggesting reduced soil acidity and increased liming.Total nitrogen increased by 100%;other nutrients(Ca^2+,Mg^2+and K^+)also increased.Increase in nutrients had a significant effect on the growth of E.grandis;larger and taller trees were associated more with burned than unburned sites.This study provides evidence that burning accumulated slash during land preparation prior to plantation establishment alters soil nutrient status and enhances the growth of E.grandis.
