Preliminary Study On Surface Combustibles In Shenyang National Forest Park

The forest surface combustible is the important condition for the forest fire.Research of forest surface fuel loading quantity,diameter class type,moisture content and relevant characteristics for the forest fire prevention,forest fire control scale,the effective management of the forest surface fuel is of great significance.This paper studied the combustibles of different forest types in shenyang national forest park,investigation and research such as the main forest types and plant species composition and amount of fuel moisture content and load level,litter species composition and the diameter distribution,the balance of the small fuel moisture content in time lag data and so on,analyzed the effects of the ground conditions and the factors on the load and moisture content of different forest surface fuel,the influence of the type composition and the diameter distribution of the small combustible materials on the time delay of the equilibrium moisture content,research conclusions as follows:(1)The main forest types and tree species composition of shenyang national forest park were investigated by field survey,result display:shenyang national forest park with larch pure forest,fraxinus rhynchophylla pure forest,quercus pure forest,elm pure forest,birch pure forest,armeniaca sibirica pure forest,pure stand of live oak,bird cherry pure forest,pinus tabulaeformis pure forest,robinia pure forest,a total of 10 kinds of main forest types.The combustibles under different forest types are mainly shrub layer,herb layer and litter layer 3layers.Each forest type of plant species composition is different.(2)The water content and load of the main forest surface fuel of shenyang national forest park were investigated and studied by the field sampling survey method and the indoor sample weighing method,result display:The moisture content reached more than 30%of the forest type,including the bird cherry pure forest(36.30%),the birch pure forest(31.46%)and the no.12 shaw(34.34%),the forest type with large load is no.2 larch pure forest(47.53 t/hm~2)and no.20 oil pine pure forest(41.28 t/hm~2).The higher the slope,the smaller the moisture content of the fuel and the larger the load.The moisture content of the combustible material in sunny slope is lower than that of the shady-slope,and the load in sunny slope is higher than the shady-slope.The higher the age of stand,the lower the fuel moisture content and the load.The higher the density of the forest,the lower the flammable content and the higher the load.(3)The types of litters of different forest types were classified in species and diameter class by hierarchical weighing method,result display:Most forest litter contains withered branches,fallen leaves(needles),bark,weeds,some forest litters are also mixed with pods,deadwood,cones,large fungi,feathers and other combustible materials.Divide litters into 8diameters for determination,most of the forest litters are distributed in two diameters of less-than 0.2cm and 0.2-0.4cm.Among them,the litters distribution in the diameter of less-than 0.2cm is the largest and most abundant.(4)The moisture content and time delay of the small combustible materials in different forest types were measured by indoor measurement method,result display:The proportion of leaves or pine needles is proportional to the equilibrium moisture content of the fuel,the proportion of combustible under 0.2cm is also proportional to the equilibrium moisture content of fuel;the larger the proportion of leaves,pine needles and branches,the greater the time lag of fuel,the greater the proportion of combustible material within 0.4cm,the greater the time lag of fuel.Among them,the size of leaf area has a great influence on the moisture content and time delay of fuel,the larger the leaf area,the lower the equilibrium moisture content and time lag of combustible materials.