Trait Differences And Influencing Factors Of Korean Pine With Coarse And Fine Bark

Korean pine,as a constructive species of mixed broadleaved-Korean pine forest in the eastern mountainous area of northeast China,is an important tree species to maintain ecosystem stability,with high ecological benefits and economic value.Korean pine can be divided into coarse bark and fine bark based on the bark morphology.Based on the dynamic monitoring sample plot of broad-leaved Korean pine forest in Fenglin National Nature Reserve of Heilongjiang Province,this study took Korean pine with coarse bark and fine bark as the main research objects to explore the differences between the two bark types and the impact of topography and soil factors on their bark traits,distribution and growth,thus enriching the understanding of the two bark types of Korean pine.The purpose of this paper is to provide a theoretical basis for scientific protection of broadleaved-Korean pine forests and suitable trees for the site.There were significant differences in bark traits,tree configuration traits,breast height cross-sectional area growth,and diameter class distribution between Korean pine with coarse bark and fine bark.The contents of morphological traits(bark thickness and bark fissure index)and defensive traits(total phenols,tannins,and flavonoids)in the bark of Korean pine with coarse bark were significantly higher than those of Korean pine with fine bark,and the carbon content in the bark was significantly higher than that of Korean pine with fine bark,while the nitrogen content was significantly lower than that of Korean pine with fine bark.The higher content of defense traits in the bark of Korean pine with coarse bark,the lower content of chemical traits,and a more conservative survival strategy exists.However,the higher content of chemical traits in the bark of Korean pine with fine bark,the lower content of defense traits,and this is an acquisitive survival strategy.The tree height and crown diameter ratio of Korean pine with coarse bark were significantly higher than those of Korean pine with fine bark,and the sharpness was significantly lower than that of Korean pine with fine bark;the 5-year growth of chest height and cross-sectional area of Korean pine with coarse bark was significantly higher than that of Korean pine with fine bark;the diameter class structure of Korean pine with coarse bark presents an approximate normal distribution,while the diameter class structure of Korean pine with fine bark presents an approximate inverse "J" type distribution.The explanation rates of micro-topography and soil factors on the bark traits,distribution and growth of Korean pine with coarse and fine bark were basically the same.Among the micro-topographic factors,slope,slope position and slope aspect have great influence on the bark traits of Korean pine with coarse and fine bark,while concavity,slope aspect and slope have great influence on distribution and growth.Among the soil factors,soil organic carbon,total nitrogen content and water content have great influence on the bark traits of Korean pine with coarse and fine bark,while soil density,water content and total phosphorus content have great influence on distribution and growth.The distribution of Korean pine with coarse bark and fine bark are similar,and they both mainly prefer the micro-topography with large slope,sunny and semi-sunny slope aspect,and convex topography.In addition,Korean pine with coarse bark also prefers the uphill with a slope of 6°～ 15°.Korean pine with fine bark also prefers medium slope position.There are significant differences in the distribution numbers of Korean pine with coarse and fine bark in any topographic dimension.According to the research results,there are significant differences in bark characters,tree configuration,distribution and growth between Korean pine with coarse and fine bark,but micro-topography and soil factors are not the factors leading to the difference,and other reasons need to be investigated and studied later.The results can provide reference for the protection and management of Korean pine natural forest and the construction of Korean pine plantation,providing data support for the construction of national reserve forests.