摘要
在吉林省露水河林业局东升林场红松(Pinus koraiensis)天然针阔混交林内设置100 m×100 m试验样地;在样地内,选择0.10、0.15、0.55、0.65、0.75不同郁闭度,以天然更新的红松幼苗为中心,设置20 m×20 m的标准样方9个,其中郁闭度0.10、0.15的部分为林窗,林窗内共设置样方3个(郁闭度0.10的设置1个,郁闭度0.15的设置2个),其它每个等级郁闭度的设置样方2个。依据试验设计,测量红松幼苗的苗高及地径;以目标红松幼苗为中心、15 m距离为半径,测量区划范围内红松母树及阔叶伴生树种的数量、树高、胸径、冠幅、活冠长、幼苗与红松母树的距离、幼苗与伴生树种的距离。以影响红松幼苗生长微生境的8个影响因素(郁闭度、冠高比、高径比、树冠伸展度、树冠体积、冠距比、红松母树数量、阔叶伴生指标)为评价指标,采用因子分析、聚类分析、二次多项式逐步回归分析等方法,筛选影响红松幼苗更新的主要微生境指标,构建红松幼苗生长适宜微生境的评价模型。结果表明:随着郁闭度的增加红松幼苗更新数量有减少的趋势,且幼苗的高度及地径均有变小的趋势。幼苗的数量在不同郁闭度间差异显著,苗高和地径在低郁闭度时显著大于中、高郁闭度时。采用因子分析法确定影响红松幼苗生长环境的4个上层乔木指数,分别为冠层结构指数(U_(1):与母树冠高比呈负相关,与郁闭度、母树高径比呈正相关的影响红松幼苗生长的微生境指标)、母树树冠大小指数(U_(2):与母树树冠伸展度、母树树冠体积呈正相关的影响红松幼苗生长的微生境指标)、母树庇荫指数(U_(3):与母树冠距比呈正相关、与母树数量呈负相关的影响红松幼苗生长的微生境指标)、伴生指数(U_(4):与阔叶伴生指标呈负相关的影响红松幼苗生长的微生境指标)。按相关度对各指数重新进行权重分配,得到红松幼苗生长的微生境综合得分(U)评价模型U=0.350 U_(1)+0.234 U_(2)+0.219 U_(3)+0.196 U_(4)。运用系统聚类法将影响红松幼苗生长的微生境进行等级划分,将微生境划分为3个等级时,各指标在不同等级间存在显著差异。根据4个指数与微生境等级间的相关关系,应用二次多项式逐步回归法,构建红松幼苗生长环境适宜度(H)评价模型H=1.941-1.721 U_(2)-2.628 U_(4)-2.736 U_(2)1-1.276 U_(2)4-2.372 U_(1) U_(2)+1.586 U_(1) U_(4)-3.222 U_(2) U_(3),模型决定系数为0.93、F=40.53、p<0.01,拟合程度较好;均方误差(MSE)值与平均绝对百分比误差(MAPE)值均为0.03,表明模型预测精度较高。
We set up the sample plot in the natural coniferous and broad-leaved mixed forest of Korean pine(Pinus koraiensis)in Dongsheng Forest Station of Lushuihe Forestry Bureau of Jilin Province,with the sample plot of 100 m×100 m.In the sample plot,we selected 0.10,0.15,0.55,0.65 and 0.75 different canopy densities,and set 9 standard quadrats(20 m×20 m)with the natural regeneration of Korean pine seedlings as the center.Among them,the part with the canopy density of 0.10 and 0.15 is the forest gap.The three quadrats were set in the forest gap(one for the canopy density of 0.10,two for the canopy density of 0.15),and 2 for the other levels of canopy density.According to the experimental design,measure the seedling height and ground diameter of Korean pine seedlings.With the target Korean pine seedlings as the center and the 15 m distance as the radius,we measured the number of Korean pine seed trees and the number,tree height,DBH,crown width,live crown length of broad-leaved associated trees,the distance between the seedlings and the Korean pine seed trees,and the distance between the seedlings and the associated trees within the division.With 8 influencing factors(canopy density,crown height ratio,height-diameter ratio,crown extension,crown volume,crown spacing ratio,number of seed trees of Korean pine,and broad-leaved associated indicators)that affect the growth microhabitat of Korean pine seedlings as evaluation indicators,factor analysis,cluster analysis,quadratic polynomial stepwise regression analysis and other methods were used to screen the main microhabitat indicators that affect the regeneration of Korean pine seedlings,and built an evaluation model of the suitable microhabitat for the growth of Korean pine seedlings.The results showed that with the increase of canopy density,the number of regeneration of Korean pine seedlings tended to decrease,and the height and diameter of seedlings tended to decrease.The number of seedlings was significantly different under different canopy density,and the seedling height and ground diameter were significantly higher under low canopy density than those under medium and high canopy density.The factor analysis method was used to determine the four upper arbor indexes affecting the growth environment of Korean pine seedlings,which were the canopy structure index(U_(1):the micro-environment index affecting the growth of Korean pine seedlings that was negatively correlated with the crown height ratio of the mother tree,and positively correlated with the canopy closure and the height-diameter ratio of the mother tree),the crown size index of the mother tree(U_(2):the micro-environment index affecting the growth of Korean pine seedlings that was positively correlated with the crown elongation and the crown volume of the mother tree),and the shade index of the mother tree(U_(3):the micro-environment index that affects the growth of Korean pine seedlings with a positive correlation with the ratio of the crown to the distance of the mother tree and a negative correlation with the number of mother trees),and the associated index(U_(4):the micro-environment index that affects the growth of Korean pine seedlings with a negative correlation with the broad-leaved associated index).The weight of each index was redistributed according to the correlation degree,and obtained the evaluation model of the comprehensive score(U)of the microhabitat for the growth of Korean pine seedlings:U=0.350 U_(1)+0.234 U_(2)+0.219 U_(3)+0.196 U_(4).The microhabitats affecting the growth of Korean pine seedlings were graded by using the system cluster method.When the microhabitats were divided into three grades,there were significant differences among the different grades.According to the correlation between the four indexes and the level of microhabitat,the evaluation model of the suitability(H)of the growth environment of Korean pine seedlings was constructed(H=1.941-1.721U_(2)-2.628U_(4)-2.736U_(2)1-1.276U_(2)4-2.372U_(1)U_(2)+1.586U_(1)U_(4)-3.222U_(2)U_(3))by using the quadratic polynomial stepwise regression method.The model determination coefficient was 0.93,F=40.53,p<0.01,and the fitting degree was good.The mean square error(MSE)and the mean absolute percentage error(MAPE)were both 0.03,indicating that the prediction accuracy of the model is high.
作者
金桂香
刘庚
于鑫
林玉梅
贾庆彬
Jin Guixiang;Liu Geng;Yu Xin;Lin Yumei;Jia Qingbin(Jilin Provincial Academy of Forestry Science,Changchun 130033,P.R.China;Tonghua County Forestry Station)
出处
《东北林业大学学报》
CAS
CSCD
北大核心
2023年第4期20-25,49,共7页
Journal of Northeast Forestry University
基金
吉林省林业重大科技攻关计划项目(2015-001)
“十三五”国家重点研发计划项目(2017YFD0601103-01)。
关键词
红松
幼苗更新
微生境
指标评价体系
Pinus koraiensis
Seeding recruitment
Microhabitat
Evaluation system
