Responses Of Wood Properties And Carbon Sequestration Characteristics To Factors Affecting Formation Of Larch Plantation

In China,The demand for wood has been increased,and the logging ban has been posed and seriously performed for the natural forests in northeast China.The developing trend of plantation has become to grasp the opportunity to cultivate high quality mature plantation,and provide quality raw materials for the future market,and improve local ecological environment.This paper discussed the annual variation and response condition of larch plantation wood properties and carbon sequestration characteristics to influence factors based on the important position of larch plantation in northeast China.The aim of this paper is study the responses of larch plantation wood to artificial cultivation measures and climate change.And the annual change rule of the properties was been modelled.The environmental effects of larch plantation management was been evaluated.The conclusions of this research were as follows:The initial planting density,slope position,stand structure and thinning intensity was been chosen as the obvious effects of these measures on larch plantation.And the response of wood properties and carbon sequestration characteristics to different levels cultivation measures was been studied.The variation of these properties under different level was been compared and regression fitting.The suitable cultivation measures can help to improve the wood properties and carbon sequestration of larch plantation wood.Wood produced in initial planting density 3.0m×3.0m showed good radial growth ability,but physical and mechanical properties are poor due to the larger average microfibril angle.Wood produced in initial planting density 2.0m×2.0m presented the lagest tracheid length,length width ratio,cell wall ratio which suitable for fiber and pulp.The wood originated from slope foot and middle has higher level than the wood from hillsid.Greater average of wood properies belong to mixed forest,and wood from serious thinning intensity stand displayed high-grade properties than wood from light thinning forest.The trend of wood properties and carbon sequestration can be fitted by different regression equation types in order to simulate the change law.The maximum annual DBH increment(without bark)was at the third to sixth growth ring age,the same as average increment.However the annual and average carbon sequestration increased sustained.The mean temperature,extreme minimum and maximum temperature,precipitation,relative humidity and sunshine hours was been chosen as the major climatic features.In the research,annual and monthly change of climate was discussed.In this study,the series of wood characteristics has been standardized by regression fitting method,H-P filtering method and multi sample average method to chronology before correlation analysis with climate change.After the short term response analysis,the long-term relationship between larch wood properties and climate was been confirmed by ARDL bound testing.The annual average humidity significantly correlated with cell wall ratio.But annual variation of monthly climatic factor closely related to wood properties.There was a negative correlation between air temperature of annual early growing season and wood properties,but the relationship between air temperature of annual late growing season and wood properties was positive correlation.There was a positive correlation between precipitation of annual late growing season and tracheid length,but negative to tracheid diameter and carbon sequestration.Relative humidity at the beginning and end of growing season has negative correlation with tracheid length and width,but positive to others.The sunshine hours of June was negative to tracheid length width ratio,and the sunshine hours of July and September was positive to annual carbon sequestration.The monthly climatic condition at the previous year also correlate with the following year wood properties.The annual extreme minimum and maximum temperature,and sunshine hours of the previous year,the mean monthly temperature of October,the extreme minimum and maximum temperature of August and December,the extreme maximum temperature of September and November,precipitation in July,the relative humidity of July,September,October and December,the sunshine hours of July,August,October and December all illustrate the late growth season and winter dormancy of previous year can influence the wood properties of following years.Wood properties of larch plantation had long term stable remarkable relationship with climatic conditions.The correlation degree of microfibril angle,carbon content and carbon sequestration with climatic change is lower.The models was been built for larch plantation wood properties and carbon sequestration based on the basic theory and modeling method of time series autoregressive moving average model(ARMA)in order to investigate the change law.The simulation results show that the ARMA method is suitable for the simulation of wood properties and carbon sequestration time series with difference processing.The series of wood properties and carbon sequestration was been analyzed by mutation test and wavelet analysis based on Mann-Kendall test and Morlet wavelet analysis method in order to explore the information hidden in the wood properties and carbon sequestration time series of larch plantation.Most mutation of wood properties series occurs at 6a of growth ring ages.The M-K test can clearly distinguish the change trend and mutation point of wood property and carbon sequestration time series.The real part of wavelet coefficients of the contour line and the variance map provided by Morlet wavelet analysis can determine the periodicity hiddened in tracheid length series which shown on 17-22 time scale,and growth rate showed strong periodicity in the 3-27a time scale.The others series does not appear obvious cyclicity probably because the limits of growth time in this study.The environmental effect evaluation of larch plantation management was been done based on LCA for optimize the existing management m nres of larch plantation.The functional unit of this study is taken as 1 ha mature forest,and the scenario included stand establishment,tending of young forest and thinning.Further,weeding process during the life cycle of mature forest seems to be the main contributor to almost all the impact categories with high contributing ratios.Production and further the application of herbicides during the process of weeding leading to release of nitrogen and ammonia into the environment.The impacts related to the use and the production of herbicides,insecticides and fertilizers.