【作者】 王建军；

【导师】 邓华锋； 孟京辉；

【作者基本信息】 北京林业大学 ， 森林经理学， 2017， 硕士

【摘要】 中国林科院热带林业实验中心(以下简称“热林中心”)的马尾松林包括人工林和近自然林两类,马尾松是我国主要的用材树种之一,在我国的森林资源总量中占有很重要的地位。如何采用正确的经营方法管理马尾松林,稳定高效的发挥马尾松林的经济、社会和生态效益是目前森林经营的主要问题。本研究以热林中心的马尾松林为研究对象,一是构建马尾松人工林的密度控制图,根据密度控制图对马尾松人工林的密度进行管理,合理的密度管理能提高人工林生产力,促进人工林的健康发展;二是针对马尾松近自然改造林,通过建立马尾松和改造树种的单木生长模型,模拟单株林木在近自然改造后的生长规律,为下一步森林经营措施的制定提供了决策依据。本研究基于热林中心建立的238块固定样地的调查数据,采用Reineke自然稀疏方程,建立马尾松的密度控制图,并采用构建的密度控制图建立了热林中心马尾松人工林密度预警图,并根据马尾松的密度状态制订了密度调控经营措施。其次,基于广西热林中心伏波试验场的20块马尾松近自然改造样地,以林木生长量为因变量,林木大小、立地条件及林木竞争指数为自变量,采用多元线性逐步回归的方法,构建马尾松以及珍贵阔叶树种的胸高断面积生长模型。对构建的模型,利用方差膨胀因子进行多重共线性分析,删除共线性较大的变量,得到最终胸高断面积生长模型,为近自然化改造林后继经营提供决策支持。主要结论如下:(1)马尾松人工林经营密度控制图的研建及应用采用RMA回归,构建了赖内克自疏方程。并根据马尾松的初始密度,构建了了马尾松人工林最优密度上限方程、最优密度下限方程和马尾松林分郁闭线,同时在密度控制图中加入了马尾松优势高模型、马尾松材积模型作为密度控制图的辅助方程。构建马尾松密度控制图,为热林中心合理经营马尾松人工林提供参考。(2)马尾松人工林密度预警图及热林中心人工林经营管理措施的制定根据构建的密度控制图以及二类调查数据,当马尾松人工林的密度在最优密度上限与最优密度下限的区间时,林分处于稳定状态;处于密度上限和密度下限以外的林分稳定性低。将不同区域的林分用不同的颜色标出,根据林分所处的状态制定不同的森林经营措施,为合理开展经营提供依据。(3)近自然改造林马尾松生长模型的构建研究表明,林木的大小D2、1/D、比对象木大的所有林木的胸高断面积之和BAL和对象木胸径平方与样地内的平均胸径(Relative.dbh2)之比等竞争因子、土壤因子对林木的生长影响显著,模型的R2在0.7以上,预估效果很好。检验数据的RMSE为0.2547,Bias为-0.00281,说明模型具有一定的稳定性,可以很好的描述马尾松林木的生长。(4)珍贵阔叶树种的生长模型研究的结果表明林木大小D2,1/D,D以及土壤条件对阔叶树的生长影响较显著。阔叶树是补植树种,在初期阔叶树的胸高断面积相对较小,受马尾松的影响较大,阔叶树之间没有发生光照、空间以及营养的竞争,林木生长初期主要的影响因素是林木自身的大小以及土壤条件。检验数据的RMSE为0.3876,Bias为0.003108。模型有较好的稳定性,预估的较准确。更多还原

【Abstract】 China has the largest plantations in the world,and Pinus massoniana is one of the largest species of plantation which is widely distributed in South china.It is especially necessary to develop right management techniques for achieving their sustainable and multiple benefit.We take two measures to manage the Pinus massoniana plantation.Frist,To manage Pinus massoniana plantation,We Constructed the stand density managemengt diagram(SDMDS),and in order to maximize the forest function and guarantee the forest productivity,it is very important for the stand to maintain suitable density.Second,Close-to-Nature management for masson pine plantation,and constructing the individual tree growth model,Individual tree growth model predict the scenario of tree growth under certain site condition and thereby provide supportive information for formulating forest management regimes.We took 238 permanent sample plots as research object in the Center of Tropical Forestry.We Constructed the stand density managemengt diagram(SDMDS)for Pinus massoniana based on Reineke self-thinning equation.Due to the diagram,scenarios of variours management options were modeled to dertermine the best management option.Then we developed the denstiy stability plot for the Center of Tropical Forestry,which provided reference for judging the stability of Pinus massoniana plantation and put forward the management measures of density control.The study was based on the 20 plots of close-to-nature transformation forests in the Center of Tropical Forestry which is sited at Pingxiang County of Guangxi Province.The growth of basal area can be described as a linear function of tree size,site condition and competition.Finally,stepwise multiple linear regression were performed to produce the individual basal area growth model for Pinus Massoniana and precious broad-leaved trees.The resultant model was further refined using variance inflection factor(VIF)to investigate multicollinearity.The variables with large VIF were deleted from the model.(1)Construction and application of density management diagramWith RMA regression,self-thinning line of Pinus massoniana lanceolata plantation was developed.Whatsmore,the optimum growth interval line was determined as well as the canopy closure line.Developed dominant height model Tree volume model and site index model as the associated relationships for SDMDs,For the reasonable arrangement of operating density to provide a reference,we modeled the scenario of various management options by the diagram.(2)The stability evalua of Pinus massonianaAccording to the stand density managemengt diagram andforest resource inventory data to judgedthe stability of the stand,Between the line for up and lower density limit is tability,the other is not.different stands marked with different color,According to the state of forest stand to develop different forest management measures,to support the decision making of rational harvesting.(3)Individual accretion of close-to-nature transformation forestThe final predictive model included tree size of D2 1/D,competition indices which included the basal area in larger trees,The ratio of the square of diameter of subject trees to the average diameter of the plots and site condition.Model of R2 is over 0.7,the estimated effect is very good.The RMSE of the test model is 0.2547 and Bias is-0.00281,which indicates that the model has a certain stability and can well describe the growth of Pinus massoniana trees.(4)Individual accretion of precious broad-leaved treesThe research indicates tree size of D2.1/D,D,and site condition had a significant effect on the growth of broadleaf trees.In the early broad-leaved trees,the chest-high cross-sectional area is relatively small and influenced by Pinus massoniana.There is no competition between light and space in the broad-leaved trees.The main factors affecting the growth of trees are the trees themselves Size and soil conditions.The RMSE of the tested broad-leaved tree model was 0.3876 and Bias was 0.003108.The model has a better stability,the estimated more accurate.更多还原