The Study Of Pinus Tabuliformis Seedlings Growth And Architecture Of Different Habitats In Huanglong Mountain

Pinus tabuliformis is the main afforestation tree species in Shaanxi Loess Plateau,with good ecological functions,such as soil and water conservation is a major building group of warm temperate forest and plantation is the most important tree species.This study Huang Longshan P.tabuliformis plantation in the southern loess plateau as an object,by comparing the different slope direction of P.tabuliformis plantation community structure and community features.Selection due to slope to update is better than sunny slope,slope to Lin window as the research object,by monitoring theory after the formation of P.tabuliformis seedlings under different big kobayashi window of young age structure,height,base diameter,long needles,root morphology,root leaf biomass were investigated,such as,analysis of P.tabuliformis under different big kobayashi window configuration as well as the influence of the branch of the west in the vertical distribution of the trunk,clarify the west P.tabuliformis configuration factors of habitat adaptation strategy,the relationship between the configuration and habitat for tending thinning measures,provides the basis for optimizing the structure of the forest.The main conclusions were as follows:1、The analysis of population structure and plantation community characteristics of P.tabuliformis plantations in Loess Plateau in different aspects showed: On the opposite,in30-years old P.tabuliformis plantations(thinned once)the growth situation,species diversity,the contents of available P,NH+4-N and NO-3-N had significant differences,meanwhile shady aspect was higher than sunny aspect.In the 50-years old P.tabuliformis plantations(thinned twice)the trees diameter had no significant difference,while there were big-diameter individuals on the shady aspect.Average tree height,seedling natural regeneration,species diversity and soil chracteristics of 50-years old P.tabuliformis plantations on the shady aspect were obvious better than on the sunny aspect.P.tabuliformis was suitable for planting both on the sunny and shady aspects in Huanglong forest region,but in the perspective of sustainable development,the shady aspect had better site condition.2、From aerial parts of seedlings under different big kobayashi window configurations and growth have obvious differences: The growth of the tree height,base diameter,crown width and coniferous leaf of the seedling grows with the increase of the gap of the gap,which also indicated that the seedlings grew faster in the large forest and shortened the seedlings into the main forest Of the time,beneficial to the regeneration of P.tabuliformis population.3、Tending thinning had effect on underground root morphology of P.tabuliformis.After thinned by different intensity,by promoting the longitudinal and transverse elongation of root,increasing root surface area and volume,and adjusting lateral root branching rate,diameter,lateral root length,angle between lateral root and taproot,and interval between lateral root to adapt the environment,absorb more nutrients and water resources,and providethe needs of nutrients and support for above ground part.With the increase of thinning intensity,dry matter allocated to the roots of P.tabuliformis.4、The biomass of P.tabuliformis.seedlings was affected by the size of forest window.Depending on the size of the gap,forest or window in the light conditions small gap is weak,the seedlings of P.tabuliformis.branches proportion of biomass may be part of larger seedlings to obtain more resources through increased investment in the branch department;middle and large gap in the light intensity increased,leaf biomass above ground larger proportion then,by increasing the blade investment to more efficient use of resources.With the increase of the forest window area,the dry matter of the roots distributed to the seedlings of P.tabuliformis.increased gradually,and the growth of the root system promoted by the large gap was the biggest.These results indicate that P.tabuliformis.seedlings can adjust phenotypic plasticity through biomass allocation.