Reaserch On The Characteristics Of Regeneration Seedlings In Different Density Of Natural Secondary Coniferous Forest In Guandi Mountain

Forest regeneration plays an important role in enriching the composition of the tree species and improving the stability of the forest ecosystem.Forest regeneration is mainly achieved through the regeneration of young trees and seedlings,and their status of renewal determines the trend of future community development.Picea asperata and Larix principis-rupprechtii are main tree species of cold temperate evergreen coniferous forests.They play very important role in natural regeneration,reproduction of forest resources and restoration of degraded ecosystems in mountain secondary forests in North China.This paper takes Shanxi Guandi Mountain different density of natural secondary coniferous forest(Picea asperata forest,Larix principis-rupprechtii forest,mixed forest of Picea asperata and Larix principis-rupprechtii)as the research object,the main coniferous forest regeneration and the use of statistical methods to explore the spatial point pattern analysis of regeneration seedlings density characteristics,age structure and space distribution pattern.The results of the study are as follows:(1)The regeneration seedlings of the needles in the Picea asperata forest are mainly Picea asperata.With the increase of stand density,the density of Picea asperata increased first and then decreased.The distribution of the age structure of the regeneration seedlings was inverted J.Under the low density and high density forest,the proportion of the 1?3 years old was larger.Under the high density stand,the number of 10?18 years old is very few.The regeneration seedlings were aggregated and distributed.With the increase of the density of the stand,the aggregation degree of the regeneration seedlings decreased first and then increased.(2)The regeneration seedlings of Larix principis-rupprechtii are mainly the regeneration seedlings of Larix principis-rupprechtii and Picea asperata.With the increase of the stand density,the density of the regeneration seedlings of Larix principis-rupprechtii gradually decreased,and the density of the Picea asperata was gradually increased.The age of regenerated seedlings of Larix principis-rupprechiii was 1?3 years old on the whole.In the three density cases,the number of 1-3 years old seedlings was far greater than the other age,and the number of 10?18 years old was very small.There was a fault phenomenon in the age structure under the high density stand,and no 10?15 years old seedlings were found.The age of Picea asperata regeneration is 4-6 years old.Under the three densities,the age structure of the regeneration seedlings could remain relatively stable.As the density of the stand increases,the aggregation degree of the regeneration seedlings of Larix principis-rupprechtii was gradually increased,and the aggregation degree of Picea asperata was gradually reduced.(3)The regeneration seedlings of the coniferous leaves in the mixed forest of Picea asperata and Larix principis-rupprechtii are mainly Picea asperata regeneration seedlings.With the increase of the density of the stand,the density of the regeneration seedlings increased gradually.The age structure of the regeneration seedlings was inverted J distribution,and the whole was relatively stable.Under low density and high density forest,the number of 1?3 years old is much larger than that of other age.Under the three densities,the Picea asperata seedlings could be maintained relatively stable after 3 years of age.The regeneration seedlings of Picea asperata were clustered and distributed.With the increase of the stand density,the degree of aggregation of the regeneration seedlings gradually decreased.(4)There are obvious differences about the number and characteristics of regeneration seedlings under forest in the same density and different stand.According to the composition of the regeneration of the seedlings under the forest,Picea asperata regeneration seedlings were found under three types of forest,which showed better under forest regeneration.In terms of the number of plantlets updated under the forest,in the forest of the same density,more Picea asperata regeneration seedlings were found under the Picea asperata forest,and the lowest under the Larix principis-rupprechtii forest.In terms of the age structure of the regeneration of the seedlings under the forest,The proportion of 1?3 years Picea aspera asp regeneration seedlings was larger in Picea asperata forest and mixed forest of Picea asperata and Larix principis-rupprechtii.The proportion of 4?6 years old Picea asperata regeneration seedlings in Larix principis-rupprechtii forest is larger.But under the high density Picea asperata forest,the proportion of Picea asperata regeneration seedlings in 10?18 years is very small.The proportion of 10?18 years Picea asperata regeneration seedlings is relatively large in the Picea asperata forest and mixed forest of Picea asperata and Larix principis-rupprechtii.According to the distribution pattern of seedlings,Under the same density,the aggregation pattern of Picea asperata regeneration seedlings under Picea asperata forest was the most obvious,and the aggregation pattern of Picea asperata regeneration seedlings was not obvious in Larix principis-rupprechtii forest.