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1.
利用对白榆、加杨、旱柳、白腊4种纯林的“二类调查”的967个角规样点的角规控制胸径检尺的调查资料,分别对这4个树种组成的纯林的平均树高与平均胸径的关系进行了回归分析。结果表明,这4种人工林的平均树高与平均胸径之间存在着相关关系,即H=a+blnD,且相关紧密。在内蒙西部荒漠地区,用胸径估测平均树高对于人工林资源清查具有指导意义。 相似文献
2.
利用对白榆，加杨，旱柳，白腊４种纯林的“二类调查”的９６７个角规样点的角规控制胸径检尺的调查资料，分别对这４个树种组成的纯林的平均树高与平均胸径的关系进行了回归分析。结果表明，这４种人工林的平均树高与平均胸径之间存在着相关关系，即Ｈ＝ａ＋ｂｌｎＤ，且相关紧密。在内蒙西部荒漠地区，用胸径估测平均树高对于人工林资源清查具有指导意义。 相似文献
3.
对不同修枝强度下杉木林的生长及其与时间的相关性进行了研究,结果表明：修枝后4a,杉木林的平均树高、平均胸径以及平均单株材积均随着修枝强度的增大而下降,枝下高随着修枝强度的增大而升高,修枝后7a至13 a ,杉木林的平均树高、平均胸径以及平均单株材积均随着修枝强度的增大先升高后下降,13年后,修枝强度为1/2的处理,平均树高为14．733±0．208 m ,平均胸径为17．733±0．289 cm ,平均单株材积为0．178±0．008 cm3,为最佳修枝强度;其平均树高与时间的相关模型为 y＝0．0142 x-0．0171,R2＝0．9465,平均胸径与时间的相关模型为 y＝1．1387 x＋3．8167,R2＝0．9672,平均单株材积与时间的相关模型为 y＝0．8489 x＋4．0991,R2＝0．9707,平均枝下高与时间的相关模型为 y＝0．5308 x＋0．7522,R2＝0．9751;各项指标与处理时间的相关性均达到极显著水平（P＜0．01）。 相似文献
4.
樟树无性系组培苗丘陵山地造林早期生长分析 总被引：1，自引：0，他引：1
以樟树(Cinnamomum camphora)无性系组培苗营建试验林,对林木1~5a生生长情况进行调查分析。结果表明：1a生幼林的平均树高和冠幅的分别为1.12m和1.1m;3a生平均树高、平均冠幅和平均胸径分别为3.34m、1.4m和2.94cm;5a生平均树高、平均冠幅和平均胸径依次为5.35m、1.68m和4.8cm,分别比3a生时增加60.01%、20.1%和63.26%。不同林龄的树高有极显著差异（P＜0.01）;5a生和3a生的胸径有显著差异（P＜0.05）,但冠幅差异不显著。树高、冠幅和胸径在区间组间差异均不显著,表明群体的生长表现较一致。 相似文献
5.
以12 a生鹅掌楸属种间杂交子代测定林为对象,利用连年生长数据进行了生长差异性分析、相关分析和生长动态分析。结果表明：12 a子代测定林平均胸径23.3 cm,平均树高14.50 m,平均材积0.229 m3,杂交组合之间连年生长差异极显著。造林后第6年与第11年胸径、树高和材积的相关系数分别为0.903、0.911、0.914,相关密切,早期选择具有较高的可靠性。杂交子代测定林的速生期为第2年～第8年,胸径、树高生长数量成熟在第8a和9a,此时材积生长仍然保持较高水平,其生长数量成熟要晚于第11年。 相似文献
6.
林木高径比变化规律的探讨 总被引：5，自引：0，他引：5
高径比是说明林木树高与胸径相关关系的一个统计指标，本文根据实测资料对１６块标准地，３９５株油松进行了研究分析，从单株木树高与胸径，径阶平均高与平均胸径，林分平均高与平均胸径，以及林分密度、林分年龄与高径比关系的变化规律中，看出研究高径比在森林调查，林业生产和科研上是具有一定理论价值和实践意义。 相似文献
7.
福建茫荡山天然小叶青冈生长规律研究 总被引：1，自引：1，他引：0
在福建省茫荡山自然保护区天然小叶青冈(Cyclobalanopsis myrsinaefolia(Bl.)Oerst)林设置标准地,选取小叶青冈平均木做树干解析,利用理查兹方程、逻辑斯蒂方程、对数方程、Korf方程以及二次曲线方程等方程模拟胸径、树高、材积与年龄的相关关系,并进行分析对比。结果表明:理查兹方程模拟效果最好,小叶青冈胸径与树高连年生长量达到最大值的年龄分别为25 a和22 a,而材积连年生长量在15 a时达到最大,平均生长量在25 a达到最大。 相似文献
8.
大强度抚育对油松人工林天然更新的影响 总被引：1，自引：0，他引：1
以油松人工林为研究对象,在大强度抚育条件下,通过林分层次结构、各层次林木胸径结构、树高结构及其林木分布格局等指标研究林下天然更新状况,结果表明:油松人工林在22a、32a时分别进行株数强度50%和40%的下层抚育,后经20a天然更新(林分年龄52a),林分形成明显层次结构,分为主林层、演替层及更新层,整个林分林木胸径、树高结构均呈多峰分布,其中主林层、演替层林木胸径和树高结构均呈单峰山状分布,更新层林木胸径和树高结构呈多峰分布,各林层平均胸径分别为23.2cm、12.6cm和3.1cm,平均树高分别为18.4m、14.5m和2.8m,而对照标准地胸径、树高结构均呈单峰分布,平均胸径、树高分别为18.6cm及17.9m;主林层、演替层各层林木空间分布呈均匀分布,密度分别为840株/hm~2和1 125株/hm~2,更新层林木空间分布呈聚集分布,密度为675株/hm~2,对照样地林木空间分布偏向均匀分布,密度为1 605株/hm~2。 相似文献
9.
以种质资源调查的6个样方内的青海云杉为研究对象,通过调查测量青海云杉的胸径和树高,然后利用SPSS 24.0软件插入胸径和树高散点图,通过非线性回归进行拟合度分析,结果表明:青海云杉树高与胸径的拟合公式分别为复合模型H=2.759*1.182D、增长模型H=e(1.015+0.167 D)和指数模型H=2.759*e0.167D,都能较好地反映青海云杉的胸径和树高的相互关系,从而为以后青海云杉森林资源调查提供重要的依据和数据。 相似文献
10.
以祁连山区青海云杉为研究对象,通过测量青海云杉的胸径和树高,再通过EXCEL插入散点图后进行回归分析并添加趋势线,对该地青海云杉胸径与树高关系进行研究。结果表明:祁连山区青海云杉树高与胸径的关系以对数回归模型H=5.274 6 ln(D)拟合度最高,为以后的青海云杉森林资源调查提供重要的依据和数据。 相似文献
11.
《Forest Ecology and Management》2005,204(1):115-129
General non-site-specific allometric relationships are required for the conversion of forest inventory measurements to regional scale estimates of forest carbon sequestration. To determine the most appropriate predictor variables to produce a general allometric relationship, we examined Eucalyptus pilularis aboveground biomass data from seven contrasting sites. Predictor variables included diameter at breast height (dbh), stem volume, dbh2 × H, dbh × H and height (H). The data set contained 105 trees, ranging from 6 to over 20,000 kg tree−1, with dbh ranging from 5 to 129 cm. We observed significant site differences in (1) partitioning of biomass between the stem, branch wood and foliage; (2) stem wood density and (3) relationship between dbh and height. For all predictor variables, site had a significant effect on the allometric relationships. Examination of the model residuals of the site-specific and general relationship indicated that using dbh alone as the predictor variable produced the most stable general relationship. Furthermore, the apparent site effect could be removed by the addition of a constant value to the measured diameter (dbh + 1), to account for the differing diameter distribution across the seven sites. Surprisingly, the inclusion of height as a second predictor variable decreased the performance of the general model. We have therefore demonstrated that for E. pilularis a general allometric relationship using dbh alone as the predictor variable can be as accurate as site-specific allometry, whilst being applicable to a wide range of environments, management regimes and ages. This simplifies regional estimates of aboveground biomass from inventory measurements, eliminating the need for site-specific allometric relationships or modifiers such as height, wood density or expansion factors. 相似文献
12.
密度指数与林分测树因子数学模型及应用 总被引：3，自引：1，他引：3
以落叶松（ＬａｒｉｘｇｍｅｌｉｎｉｉＲｕｐｒ．）天然林标准地为材料，选取３０块大样本标准地，通过Ｎ＝ａＤ－ｂ得出林分测树因子数学模型。Ｇ＝ａＳＤＩｂ（Ｈ－１．３）ｃ式为密度指数、树高与断面积模型；以Ｙ＝ａＳＤＩｂＸｏ式为密度指数与直径、株数、断面积的模型。模型可用于编制树高标准表、直径标准表、密度标准表以及密度控制图等。 相似文献
13.
Estimating Pinus palustris tree diameter and stem volume from tree height,crown area and stand-level parameters 总被引：1，自引：0，他引：1
C. A. Gonzalez-Benecke Salvador A. Gezan Lisa J. Samuelson Wendell P. Cropper Jr. Daniel J. Leduc Timothy A. Martin 《林业研究》2014,25(1):43-52
Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height （dbh） and merchantable stem volume （V） using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height （H） and crown area （CA）. Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data. 相似文献
14.
[目的]由于激光雷达技术已经能准确测定立木树高及相关树冠因子,应用该技术建立基于树高和树冠因子的立木材积模型,为激光技术在森林蓄积估计中提供技术支撑.[方法]利用云杉、冷杉、栎树、桦树4个树种组的3 010株实测样木数据,分析了立木材积与胸径、树高、树冠因子之间的相关关系;并通过对数回归方法构建了基于树高和树冠因子的立木材积模型,用确定系数R2和平均预估误差MPE等6项指标对模型进行评价.[结果]表明,立木材积与单一因子之间的相关,以胸径最为紧密,其次是树高,再次是冠长和冠幅.基于树高和树冠因子的立木材积模型中,以树高和冠幅作为解释变量的二元模型效果较好,再增加冠长因子的三元模型改进不大.云杉、冷杉、栎树、桦树4个树种组基于树高冠幅的立木材积模型,其R2分别为0.81、0.80、0.76和0.77,MPE分别为4.7%、5.3%、5.4%和5.3%,模型预估精度均能达到95%左右.[结论]本文对材积与林木因子之间相关关系的定量分析,建立了云杉、冷杉、栎树、桦树4个树种的立木材积模型,模型预估精度高.为激光雷达技术定量估测森林参数提供了依据. 相似文献
15.
木荷二元材积表的研制 总被引：2，自引：1，他引：2
利用样木资料,以胸径D、树高H为自变量,材积V为因变量,在多种二元材积模型筛选的基础上,选择山本公式建立木荷二元材积模型并用改进单纯形法进行优化,由此求得木荷二元材积模型为:V=0.00006801D1.865613H0.918129。该模型理论值和实际值差异不显著,实际应用误差小,精度高,完全能够满足生产上的精度要求,可在森林资源清查中推广应用。 相似文献
16.
Lianas (woody vines) are an important component of tropical forests, with a strong impact on forest dynamics, but their responses during forest succession have received relatively little attention. Here, we present an analysis of the changes in stem density, biomass, and species richness of lianas and self-supporting plants during tropical forest succession. We surveyed lianas ≥0.5 cm diameter at breast height (dbh) and self-supporting plants ≥2.5 cm dbh in 0.1 ha inventory plots in a chronosequence of 30 sites in northeastern Costa Rica, 23 sites on abandoned pastures 10–44 years of age, and seven sites in old-growth forest. Stem density of self-supporting plants showed no predictable chronosequence trend, but liana stem density declined significantly with forest age. Aboveground biomass of self-supporting vegetation increased rapidly during succession, with forests 31–44 years exhibiting higher levels of biomass than old-growth forests. Liana biomass accumulated more slowly, with the highest levels in old-growth sites. Species richness of self-supporting vegetation increased significantly during succession, but species richness of lianas showed no change or a slight decline with forest age, depending on the method of assessment. The differences between tree and liana responses during succession stem from the unique physiology and life history traits of lianas. 相似文献
17.
福建省毛竹混交林竹林结构比较研究 总被引：1，自引：0，他引：1
通过对浦城县古楼乡毛竹阔叶树混交林、毛竹杉木混交林、毛竹杉木阔叶树混交林及毛竹纯林等4种不同经营模式林分比较,结果表明:混交林毛竹个体生物量、毛竹胸径和竹高较大,不同模式林分的胸径、竹高、冠幅等生长因子有显著差异;竹阔混交林较有利于竹鞭孕芽发笋;各模式竹林结构综合评判为一般经营竹林;竹林竹鞭长、鞭径、鞭节生长以竹阔比例为5∶5林分竹鞭较好。 相似文献
18.
西藏自治区森林碳密度及分布规律研究 总被引：1，自引：0，他引：1
利用森林资源连续清查实测样地及样木数据,结合相对树高曲线,构建生物量-蓄积量模型,解决了模型与各类森林资源调查数据的衔接问题,可应用于西藏自治区森林资源连续清查的目测与遥感样地生物量估算及森林资源规划设计调查小班生物量估算等。根据计算的森林资源连续清查各样地生物量密度,结合树种面积数据及含碳率,估算全区森林碳密度,并初步探讨了森林碳库地带性分布规律。 相似文献
19.
A flexible regression model for diameter prediction 总被引：2，自引：2，他引：0
Edgar Kublin Nicole Helene Augustin Juha Lappi 《European Journal of Forest Research》2008,127(5):415-428
We present a functional regression model for diameter prediction. Usually stem form is estimated from a regression model using
dbh and height of the sample tree as predictor. With our model additional diameter observations measured at arbitrary locations
within the sample tree can be incorporated in the estimation in order to calibrate a standard prediction based on dbh and
height. For this purpose, the stem form of a sample tree is modelled as a smooth random function. The observed diameters are
assumed as independent realizations from a sample of possible trajectories of the stem contour. The population average of
the stem form within a given dbh and height class is estimated with the taper curves applied in the national forest inventory
in Germany. Tree deviation from the population average is modelled with the help of a Karhunen–Loève expansion for the random
part of the trajectory. Eigenfunctions and scores of the Karhunen–Loève expansion are estimated through conditional expectations
within the methodological framework of functional principal component analysis (FPCA). In addition to a calibrated estimation
of the stem form, FPCA provides asymptotic pointwise or simultaneous confidence intervals for the calibrated diameter predictions.
For the application of functional principal component analysis modelling the covariance function of the random process is
crucial. The main features of the functional regression model are discussed informally and demonstrated by means of practical
examples. 相似文献
20.
《Scandinavian Journal of Forest Research》2012,27(2):135-153
Adequate allometric equations are needed for estimating carbon pools of fast growing tree species in relation to international reporting of CO2 emissions and for assessing their possible contribution to increasing forest biomass resources. We developed models for predicting biomass, stem basic density and expansion factors of stem to above-ground biomass for five fast growing conifers. Data included destructive measurements of 236 trees from 14 sites, covering a wide range of growth conditions. To ensure model efficiency, models for predicting stem, crown and total above-ground biomass for the five species were estimated simultaneously using a linear, mixed effects model that allowed contemporaneous correlations between the different tree components. Models differed among species and included dbh and tree height. The models explained more than 98% of the variation in above-ground biomass and reflected differences in the allometry between tree species. Stem density differed among species but generally declined with increasing site index and dbh. The overall model for predicting stem basic density included dbh, H100 and site index and explained 66% of the total variation. Expansion factors decreased from 1.8–2.0 in small trees (dbh < 10 cm) to 1.1–1.2 for large trees (dbh > 25 cm), but differed among species. The overall model explained 86% of the variation and included quadratic mean diameter and dbh. 相似文献