油松林地表可燃物类型和径级对平衡含水率和时滞的影响

[Objective]This paper aims to analyze the equilibrium moisture content and time-tag variation characteristics of different types and different diameter classes of surface fuels,so as to provide theoretical basis for scientific management of surface fuels.[Methods]The surface fuels such as dead branches of different diameter classes,semi-humus and pine needles were collected from Pinus tabuliformis forest.The equilibrium moisture content and time-lag of each surface fuel were measured under the condition of constant temperature and humidity,and the effects of surface fuel types and diameter classes on the equilibrium moisture content and time-lag were analyzed by multiple comparison method.[Results]The equilibrium moisture content and time-lag of surface fuels were strongly affected by the types of surface fuels.The equilibrium moisture content and time-lag of semi-humus were the highest,and were significantly higher than those of pine needles and dead branches.In addition,the equilibrium moisture content and time-lag increased with the increase of dead branch diameter class,but such effects were not very significant.[Conclusions]This study is the first to find the variation of equilibrium moisture content and time-tag of forest surface fuels between different fuel types and diameter classes,which is helpful to improve the prediction and management ability of surface fuel water content in Pinus tabuliformis forest.