共查询到20条相似文献，搜索用时 375 毫秒
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本文采用数理统计方法对３３１株天然红松优树的胸径、树龄、树高进行了分析，了天然红松优树胸径，年龄，树高相关表，可为红松种子园建设中的优树选择提供依据。 相似文献
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通过外业调查白河林业局不同径级天然水曲柳胸径、树高的情况,用相关软件对数据进行整理和分析,研究白河林业局天然水曲柳的生长状况。研究结果表明,天然水曲柳多分布在10～52径级,不同径级的天然水曲柳在总体水平上差异性极显著,一元材积模型和二元材积模型的拟合度均很高,表明这两个模型均适合模拟白河林业局的天然水曲柳材积。 相似文献
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以宝龙店32+1个水曲柳家系为材料,测定其树高、胸径生长性状,估算变异系数、遗传力和遗传增益,筛选出优良家系.结果表明:各家系的树高、胸径存在较丰富变异,树高变异系数大于胸径,树高、胸径极显著相关(P<0.01),家系间树高、胸径差异均达极显著差异水平(P<0.01).以10％的入选率,初选出家系1412、1405和1... 相似文献
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水曲柳人工造林与培育技术的研究 总被引：1，自引：0，他引：1
在缓坡、轻微水湿地、农耕地等不同立地进行水曲柳人工造林,以农耕地为最佳,其次是缓坡。农耕地10 a生水曲柳人工幼林平均树高为5．430 m,为其它立地水曲柳人工幼林树高均值的150．0％,单位面积立木蓄积为其它立地立木蓄积的158．3％,树高、胸径最大值分别为6．80 m和7．3 cm,表现出较强的生长优势。水曲柳人工林生长规律为:3 a、6 a生时,树高、胸径、材积生长开始加快,速生期内胸径、树高连年生长量分别在0．40-0．67 cm之间和0．500 0-1．000 0 m之间。采用Riehards曲线进行水曲柳人工幼林树高生长过程拟合,结果为H=8．773 545×[1-EXP(-0．217 416 5 X)]3.574 767。 相似文献
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巨尾桉人工林地径与胸径、树高相关模型的研究 总被引：6，自引：0，他引：6
根据巨尾桉人工林样木的地径D0、胸径D及树高H观测数据,采用多模型选优法和逐步回归法求解方程,经分析对比后分别建立了地径与胸径、地径与树高相关的2个数学模型:lnD=3.7275-18.6673/D0;H=32.0925-244.050 3/D0。应用这2个模型,配合一元材积表或二元材积表就可测定被伐木的材积。 相似文献
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Increases in plant size and structural complexity with increasing age have important implications for water flow through trees. Water supply to the crown is influenced by both the cross-sectional area and the permeability of sapwood. It has been hypothesized that hydraulic conductivity within sapwood increases with age. We investigated changes in sapwood permeability (k) and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans F. Muell. Sapwood was sampled at breast height from trees ranging from 8 to 240 years old, and at three height positions on the main stem of 8-year-old trees. Variation in k was not significant among sampling height positions in young trees. However, k at breast height increased with tree age. This was related to increases in both vessel frequency and vessel diameter, resulting in a greater proportion of sapwood being occupied by vessel lumina. Sapwood hydraulic conductivity (the product of k and sapwood area) also increased with increasing tree age. However, at the stand level, there was a decrease in forest sapwood hydraulic conductivity with increasing stand age, because of a decrease in the number of trees per hectare. Across all ages, there were significant relationships between k and anatomy, with individual anatomical characteristics explaining 33-62% of the variation in k. There was also strong agreement between measured k and permeability predicted by the Hagen-Poiseuille equation. The results support the hypothesis of an increase in sapwood permeability at breast height with age. Further measurements are required to confirm this result at other height positions in older trees. The significance of tree-level changes in sapwood permeability for stand-level water relations is discussed. 相似文献
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利用雷州林业局刚果12号桉W 5无性系林分中胸径8~18 cm径阶,树高11~23 m的样木1 207株和尾叶桉U6无性系林分中胸径8~18 cm径阶,树高10~21 m的样木784株,按材种规格标准造材实测材积,且分别建立刚果12号桉W 5无性系和尾叶桉U6无性系胶合板材立木出材量二元回归方程,经检验精度可靠,可供参考使用。 相似文献
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M. Grut 《Southern Forests》2013,75(1):54-57
A number of equations were fitted by means of stepwise regression to data from 171 compartments enumerated for working plan purposes in the southern and south-western Cape Province. Top height (= the mean height of the 100 biggest trees per ha in terms of diameter at breast height) or a function of top height was used as the dependent variable. Mean height, age (A), stems per ha (SPH) and mean diameter at breast height were used as the independent variables. The following equation gave the best results: Top height = mean height + 0,03 log (SPH—99) A 相似文献
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幼年赤桉胸径与冠幅、树高、材积的相关性分析 总被引：2，自引：0，他引：2
对试验地的1470株赤桉进行树高、胸径、冠幅的测量,并计算出样木的单株材积。把胸径分别和冠幅、树高及株材积进行相关性分析并且建立数学模型,用SPSS软件对所选模型进行曲线估计。结果表明：其中幂方程的 R2最大,F 值亦为最大,说明赤桉胸径与树高的幂关系显著,可确定赤桉胸径与树高的最优回归方程为H=1.804D0.673。胸径—冠幅,胸径—材积的最优模型分别为CW=0.674D0.561,V=0.0001614D2.341。分别对3组最优模型进行适应性检验,结果表明：材积的3个最优回归模型预测误差均在＆#177;3%以内,方程预测精度较高,可用于估算立木树高、冠幅、材积。 相似文献
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对浙江省杉木Cunninghamia lanceolata主要分布区51个不同发育阶段杉木人工林典型样地调查,分析不同优势木高杉木人工林的径级结构,并利用126株优势木数据,建立杉木人工林优势木的胸径、树高、冠幅之间关系,得出胸径与树高相关关系的最佳回归方程为:Y=0.361 8X+4.497 9,模型的拟合度R^2=0.796 5(X表示胸径,Y表示树高);胸径和冠幅的相关关系的最佳回归方程为:Y=0.137 9X+0.858 9,模型的拟合度R^2=0.881 6(X表示胸径,Y表示冠幅)。通过对3株50年生杉木人工林大径级林分优势木的树干解析,研究大径级杉木人工林优势木的胸径、树高与材积的生长规律,结果显示生长率都呈现逐年降低趋势,树高较为明显。树高、胸径、材积生长率最大值出现在10年生时分别为5.278 7%,15.069%,25.895%;而50年生时仅为0.273 3%,0.186 9%,0.921 7%。研究提出杉木人工林目标树经营的发育阶段划分、合理密度、目标树数量等关键经营技术参数,为杉木人工林的目标树经营提供理论依据。 相似文献
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The impact of infection by Taphrina betulina on the growth of Betula pubescens was studied in naturally regenerated stands in the North East of Scotland. Infection by T. betulina was associated with a significant reduction in height growth and poorer developmental tendency, vigour, and stem quality of B. pubescens, whereas diameter at breast height was little affected. Tree height was reduced by an average of 25% over all diameter classes, with the greatest effect in smaller trees. For brooms of 100 mm diameter and over, numbers and sizes were strongly correlated with diameter at breast height and tree age. Reductions in height and vigour were not correlated with the number and size of brooms present, but were more pronounced in younger, smaller trees. 相似文献
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The research described in this paper was performed in the Niepolomice Forest (Southern Poland) in 2001 as part of the Forest
Environmental Monitoring and Management System (FOREMMS; 5FP IST) project. The material for the present study consisted of
the measurement results of the biomass of Scots pine shoots with needles and needles alone carried out on 113 felled sample
trees. The purpose of this study was to construct empirical equations for estimating the foliage biomass of Scots pine from
easy to measure parameters. To achieve this aim, the dependence of the foliage biomass of Scots pine on stem diameter, height,
age, crown length, basal area increment of the trees was analyzed. Using the biometric characteristics such as: tree diameter
at breast height (dbh), basal area increment, age, height, and crown length empirical equations for estimating the foliage
biomass of Scots pine reasonably precisely have been established. The created empirical equation gives accurate foliage biomass
estimates. The explained variability varies between 65 and 85%, it depends on the number of variables applied in the equation.
The equations presented in this paper were created with a view to their possible use in ecological studies where biomass quantity
may be used, for example, in modeling carbon circulation in the forest ecosystem. From the point of view of forestry practice,
these equations may help to assess biomass production in Scots pine stands. 相似文献
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红豆树立木的主要性状特征研究(Ⅱ) 总被引：2，自引：0，他引：2
红豆树胸高心材出现在10 a以后,相同立地环境且同龄的红豆树立木,其心材出现有迟早和大小的差别.心材材积与胸径呈幂函数关系、心材直径与胸径呈直线关系、心材直径与树高呈对数关系、心材直径与冠长呈直线关系、心材直径比率与胸径呈自然对数函数关系;红豆树心材率达2倍以上标准差进行优树选择时,可望选出选择差较大、心材比率在90.2%的优树.Ⅰ级侧枝枝粗与胸径、冠长呈直线关系,与树高关系、枝下高不存在有实际意义的相关关系.红豆树林分中,通直的Ⅰ级木占调查样本数的33.7%、Ⅱ级木占21.1%、Ⅲ级木占24.7%、Ⅳ级木占17.5%、Ⅴ级木占3%.冠长与胸径呈直线关系、与树高呈对数关系,冠幅与胸径呈对数关系. 相似文献