Study On Forest Furface Fuel In Wan Dian Zi Experimental Forest Farm Of Liaoning

Forest surface combustible is an indispensable factor for forest fire.so it is important to study the forest combustibles management and forest fire prevention under different forest types.This article mainly studies on the main forest types and the types of surface combustibles,the surface combustibles loading,the inflammability of forest floor litter and the classification of comprehensive fire danger rating in the experimental forest farm in the Wandianzi of Liaoning province.The specific research results are as follows:(1)The general survey method was used to investigate the main forest types in the experimental forest farm in the Wandianzi of Liaoning.The results showed that there were 11 main forest types,namely,Korean Pine artificial pure forest,Larch artificial pure forest,Chinese Red Pine artificial pure forest,Spruce artificial pure forest,Mongolian Pine artificial pure forest,Robur natural forest,Juglans mandshurica natural forest,northeast China ash natural forest,Ribbed birch natural forest,Aspen natural forest,and broad-leaved natural miscellaneous wood forest.Among those forests,the most common distribution of five forest types were Korean Pine artificial pure forest,Larch artificial pure forest,Spruce artificial pure forest,Robur natural forest and broad-leaved natural miscellaneous wood forest respectively.Most of the forest types were rich in surface combustibles.Generally,the coverage of broad-leaved shrubs was larger than that of needle leave trees,while the coverage of broad-leaved natural miscellaneous wood forest was obviously higher and that of the Aspen natural forest was obviously low in the herbaceous layer.The natural forest was obviously higher than artificial pure forest in the composition Of planting species.(2)By adopting the combination of field random sampling and weighing method,we studied on the surface combustibles loading of the main forest types in the field.The results showed that the surface fuel loading and water content of the 11 major forest types were very different.There are 6 forest types whose the water content were lower than 15%.In regard to the surface fuel loading,there were 2 forest types that higher than 20t/hm2,These two index were generally higher than its in other areas of the province.Considerating integrately regarding water content and surface fuel loading,there are 4 forest types whose forest fire danger rating were high:artificial pure forest of pinus sylvestris,artificial pure forest of pine,natural oak forest and natural broad-leaved miscellaneous wood forest.(3)Random sampling method was used to investigate the different forest age,densities and different slopes and slope position of main forest types.As for majority forest type,the surface combutible were generally increased with the increasing forest density.However,the two forest types of natural Juglans mandshurica forest and natural northeast China ash natural forest had the opposite performance.In different age phase,fuel loading decreased with the increasing stand age.But the difference was not obvious in the middle-aged forest and old-growth forest.In the different slope directions,the surface fuel loading on the southern slope was generally highest,while the northern slope was the lowest,and the eastern and western slopes were fallen in between.In terms of slope position,from lower abdomen to upper abdomen,the surface fuel loading tendered to decrease from lower abdomen to upper abdomen.(4)The litter layers of 11 types of forest surface combustibles were determined by indoor measurement method,and the flammability analysis was carried out by weighted method.The results showed that: Korean pine artificial pure forest,Chinese Red Pineartificial pure forest,spruce artificial pure forest and Mongolian pine artificial pure forest had the highest comprehensive scores for the flammability of floor litter,which were belonged to the most flammable forest type.The robur natural forest,northeast China ash natural forest,Ribbed birch natural forest and aspen natural forest had the lowest comprehensive scores,which meant their combustibility relatively was the worst and not easy to cause combustion.(5)The classification weighted method was used to comprehensively analyze the surface combustibles loading,moisture content and comprehensive flammability of 11 kinds of forest from three factors,and to divide the fire risk grades of different forest types.The results showed that there were three types of forests belonged to Class A fire risk grade(the most easy flammable),namely,Korean pine artificial pure forest,Chinese Red pine artificial pure forest and larch artificial pure forest;there were six types of forest types that belonged to Class B fire risk grade(relatively flammable),namely spruce artificial pure forest,Mongolian pine artificial pure forest,robur natural forest,northeast China ash natural forest,Ribbed birch natural forest and broad-leaved natural miscellaneous wood forest.There were two forest types that belonged to grade C fire risk grade(relatively non-flammable),which were aspen natural forest and Juglans mandshurica natural forest.