Population Dynamics And Spatial Patterns Of Natural Pinus Koraiensis Seedings In Eastern Liaoning Mountainous Area,China

Broadleaved-Korean pine mixed forest is the zonal climax vegetation in the eastern mountains of northeastern China.Due to long-term natural disturbance and human disturbance,only a small part of original broadleaved-Korean pine mixed forest remained.Most of the forests are degenerated into secondary forests.People planted Pinus koraiensis plantations after cutting the secondary forest.With the increasing age of P.koraiensis,a large number of P.koraiensis seedlings appeared under the condition of picking pinus seeds normally,however,they didn't develop into saplings.In order to ascertain the impact of P.koraiensis seedling update ability,this study selected three different forest types(new forestation land,broad-leaved forest and Larch plantation)which adjacent to P.koraiensis plantation,natural P.koraiensis seedings as the research object,analyzing the distribution,survival condition,age structure,population dynamics and spatial pattern of natural P.koraiensis seedings,the main conclusions are as follows:(1)Among the three different forest types,the quantity of natural regenerated P.koraiensis seedlings was the most in the broad-leaved forest,followed by the Larch plantation,new forestation land is the least.In addition,with the increase of the distance from the plantation,the number of natural P.koraiensis seedlings decreased continuously,and the maximum distribution was 600 meters away from the plantation.(2)The most natural P.koraiensis seedings are ?,?,? age class in the three different forest types,mainly distributed in the range of P.koraiensis plantation 0 to 50 meters range,however natural P.koraiensis seedlings of ?,? age class are rare and distributed regularity.(3)The age structure of the natural regenerated P.koraiensis seedlings in three different forest types showed a "?" type left skewed distribution,with a large number of seedlings in the early stage and a decreasing number in the later stage.(4)The survival rate of natural regeneration P.koraiensis seedling populations in three different forest types decreased with the increase of age,while the cumulative mortality rate increased with the increase of age.Survival curve of natural P.koraiensis in three different forest types verge to Deevey-?.Life expectancy of natural P.koraiensis in each class in new forestation land are higher than broad-leaved forest and Larch plantation.(5)The distribution of natural P.koraiensis seedling is different in three different forest types.The natural P.koraiensis seedling of new forestation land and Larch plantation distributed intermittently.The natural P.koraiensis seedling of broadleaved forest distributed continuously,but with the increase of distance of P.koraiensis plantation,the number of the seedings gradually reduce.(6)The seedlings of different age groups were mainly distributed in clusters,but in a few age groups they were distributed randomly and uniformly.The seedlings of natural renewed P.koraiensis at different distances were clustered and distributed in small scale,while in large scale,they were distributed randomly or uniformly.To sum up,P.koraiensis can achieve natural regeneration of seedlings in different forest types around P.koraiensis plantation(early stage),but the renewal range is limited(within a ring band with a radius of 600 meters),and the preserving rate of P.koraiensis seedlings decrease sharply with the increase of age.In order to ensure the survival and growth of natural P.koraiensis seedlings,it is suggested to carry out proper nuture in the area of P.koraiensis plantations to restore broadleaved-Korean pine mixed forest as soon as possible.