关键词: 可燃物, 载量, 相关分析, 冬奥会, 线性回归

Abstract:

Objective: By establishing the regression relationship between stand factors, terrain factors and forest surface combustible loads, the forest surface combustible loads of Larix principis-rupprechtii and Betula platyphylla in the core area of Chongli Winter Olympic Games were estimated, which provides a scientific basis for forest fire prevention and fuel management in this study area. Method: On the basis of 63 sample plots set in the study area in 2021, this study took stand factors(stand age, average DBH, average tree height, stand density, canopy density, vegetation coverage), terrain factors(slope, altitude, soil layer thickness) and forest surface combustible loads (fresh and dry mass of bushes, herbs, litter and humus) as the research object. After processing the data of forest surface combustibles, the correlation analysis was carried out with stand factors and terrain factors as independent variables and forest surface combustible loads as dependent variable. In order to construct the optimal model form, the stepwise screening method was used to screen out the appropriate factors. Finally, stand age, stand density, vegetation coverage and altitude were selected to estimate the total surface combustible loads of L. principis-rupprechtii forest. Besides, stand density, slope and altitude were selected to estimate the total surface combustible loads of B. platyphylla forest. Based on this, the surface combustible loads of forest land sub-compartment in the core area of Chongli Winter Olympic Games were predicted. Result: The total surface combustible loads of L. principis-rupprechtii forests were significantly higher than that of B. platyphylla forests (P < 0.05). According to the correlation analysis among the stand factors, average tree height, average DBH and canopy density were significantly correlated with the total loads of surface combustibles (P < 0.05). Among the terrain factors, slope and soil thickness were significantly correlated with the total loads of surface combustibles on the forest surface (P < 0.05). It can be seen from the construction of forest fuel load model. Stand age, stand density, vegetation coverage and altitude could be used to estimate the total surface combustible loads of L. principis-rupprechtii forest. Stand density, slope and altitude could be used to estimate the total surface combustible loads of B. platyphylla forest. The determination coefficients of two forest type models were greater than 0.6 and the P values were less than 0.01. The model verification indicators also indicated that the models had good estimation accuracy. Through the two models, the total surface combustible loads of L. principis-rupprechtii forests and B. platyphylla forests in the core area of Chongli Winter Olympic Games were estimated and the distribution map was drawn. Conclusion: The total surface combustible loads of L. principis-rupprechtii forests were significantly higher than that of B. platyphylla forests, so L. principis-rupprechtii forest might be more prone to forest fire. Moreover, the influence factors of forest surface combustible loads of different forest types were different. Therefore, when carrying out combustibles management, we should choose different management methods and control measures according to local conditions. Due to the research data source, the forest surface combustible loads models are only applicable to the core area of Chongli Winter Olympic Games, which has a certain reference value for other areas. Most of the variables in the models are easily available survey factors, which makes the models have good applicability and can provide basis for forest fire prevention.

Key words: combustibles, carrying capacity, correlation analysis, Winter Olympics, linear regression