单株立木材积测定方法的研究

单株立木材积的测定对林业生产和科学研究工作有着重要的作用,主要的测定方法是通过胸径、树高、上部直径或上部直径的高度来计算干形指数,然后计算单株立木材积。而不同的方法所用上部直径不同。本文用5个树种的解析木,分别对较常见的5种测定方法的测定精度进行了研究。得出的结论为:3/4形点法、0 5形点法、胸高形率法精度较高,绝对形率法、望高法精度较低。建议对干形饱满的树种采用3/4形点法、0 5形点法;对干形尖削的树种采用0 5形点法、胸高形率法。     

DQS—1A无标尺测树仪在累高法测定立木材积应用中的探讨

1 引言DQS—1A 无标尺测树仪研制成功以来,解决了立木上部直径测定的许多问题,促进了干形及立木材积测定方法的应用,收到了良好的效果。但是,该测树仪由于机理限制,仍不能直接应用到望高法、累高法等测定立木材积的方法中,其原因是:该仪器测定上部直径是由透镜中的分划刻度格数确定的,而每一格的格值又必须由测视距离确     

用数式法计算立木材积

立木树干材积是树干粗度(胸高直径或断面积)树高和树干形状三个因子的函数。而林分蓄积量可以理解为林分总断面积、林分平均高和林分平均干形三个因子的函数。在这三个因子中,只测树干粗度和高度两个因子,以确定立木材积或林分     

关于干形控制方法的几点意见

测算森林蓄积量的关键之一是控制干形,蓄积量的精度很大程度上取决于所用干形值的精度。本文拟就干形控制方法提几点意见。一、关于回归分析方法本方法是将实测的d_(1.3)、h与f_(1.3),用最小二乘法配合回归方程,据之估算立木材积或胸高形数。常用的方程类型有:f_(1.3)=a·d_(1.3)~b·h~c(1)和f_(1.3)=a_0 a_1/d_(1.3) a_2/h a_3/d_(1.3)~2h(2)等。这种方法的优点是:利用数据的信息较充     

几种立木材积方法的比較

立木树干材积是树干粗度(胸高直径或断面积)、树高和树干形状三个因子的函数。而林分蓄积量可以理解为林分总断面积、林分平均高和林分平均干形三个因子的函数。在这三个因子中,只测树干粗度和高度两个因子,以确定立木材积或林分蓄积量的方法,称为二元控制法。     

测定立木材积生长率的胸径法和形点法

<正> 郭永台提出测定立木材积的生长率的高径比法比普雷斯勒法简便易行,且对较大树龄的立木在一般情况下尚能达到生产要求的精度,但仍需测定树高。普雷斯勒法虽较精确,但需伐倒区分求积。为此,作者提出了胸径法和形点法,更为简易,实用。     

测定形率的新方法

在三元法立木材积测算中,通常采用A.希费尔提出的形数计算公式: f=0.66q_2~2 0.32/q_2H 0.140。这个经验公式适用于所有针阔叶乔木树种,平均误差一般不超过±3％。瑞典人荣索提出测定形率(q_2)的新方法。他提出不需直接测定树高一半处的直径,只要测定6米树高处直径,并计算出与胸径比值的百分数,再根据树高从表中直接查得形率。     

测定林分蓄积量的立体角规法

<正> 为了测定林分蓄积量,【日】北村昌美提出了一致高和法。其理论无疑是正确的。然而在林内逐株测定一致高较为麻烦和困难,所以未能推广应用。作者应用点抽样理论,根据干形的特点,将形点法推广到测定林分蓄积量,提出了立体角规法,并研制了立体角规测树仪,可简便地测定林分蓄积量。《立体角规测树仪及其测树方法》已获中国发明专利权(专利号:86101381.6)。     

YCY-01型影像测树仪的试制技术报告

为适应现代森林调查的需要,根据测高、测径,测定距离的影像测树公式[AB=(u/cosα-F)/(F·cosα)·A′B′、D=(u/cosα-F)/F·A′B′和 u=(1.5F/A′B′+F)/cosα]以及测定每公顷胸高断面积总和光学角规的原理和方法,设计试制了 YCY—01型影像测树仪。测高一次测程可达32米,既可测立木的全高也可测商品材部份的高度;能够观测任意可见部位的直径;测定距离5—40米;测量坡度±50°;可观测每公顷胸高断面积。并可推算出立木形率、立木材积,单位面积蓄积、林木组成、林分平均直径和每公顷株数等。本文对影像测树的原理方法、有关技术问题、仪器构造和主要特点以及使用方法等都作了简要的说明。     

立木材积测算精度的研究

为正确选择立木材积测算方法,提高立木材积测算精度,该文利用42株桦树、40株山杨样木的调查资料,对等直径差区分法、望高法、形率法等立木材积测算方法的精度进行了分析。结果表明,等直径差区分法:桦树的精度平均值是96.56%,山杨的精度平均值是96.97%;望高法:桦树的精度平均值是97.04%,山杨的精度平均值是95.82%;形率法:桦树的精度平均值是95.77%,山杨的精度平均值是96.80%。     

Models for estimation of tree volume in the miombo woodlands of Tanzania

Volume of trees is an important parameter in forest management, but only volume models with limited geographical and tree size coverage have previously been developed for Tanzanian miombo woodlands. This study developed models for estimating total, merchantable stem and branches volume applicable for the entire miombo woodlands of Tanzania. We used data from 158 destructively sampled trees, including 55 tree species collected from wide geographical and biophysical ranges. We developed general and site-specific models with diameter at breast height only as the independent variable, together with models with both diameter at breast height and tree height. Leave-one-out cross-validation was used to evaluate the models. The total tree volume models that included diameter at breast height and tree height had appropriate predictive capabilities with relative root mean square errors (RMSE_r) ranging from 30.5% to 47.6%. The RMSE_r for total tree volume models with diameter at breast height only ranged from 39.9% to 48.0%. The site-specific models had slightly lower RMSEr values relative to the general models. The relative mean prediction error of the general total tree volume model with diameter at breast height and tree height was lower (0.6%) than those of the previously developed models (?30.7% to 31.2%). Based on the evaluations, we recommend the general total tree models to be applied over a wide range of geographical and biophysical conditions in Tanzania.     

马尾松种源试验研究

马尾松是我国亚热带地区分布最广、资源最多的特有乡土树种.对参试的44个马尾松种源的树高、胸径、材积、枝下高和冠幅等生长指标进行了系统分析.结果表明:8年生马尾松种源试验林树高、胸径和材积生长差异显著,枝下高和冠幅生长无明显差异;树高、胸径和材积遗传力较高,分别为40.61%、39.53%和32.79%,枝下高和冠幅较低;聚类分析研究将马尾松种源分为极速生、速生和中等3种类型;综合评定的结果与聚类分析结果相符,确定了40号种源为最佳种源和33个可供采用的优良种源.     

7年生短枝木麻黄优良无性系选择的研究

以海南2个试验点上各含17个无性系的短枝木麻黄无性系为试验材料,进行树高、胸径、单株材积、主干分叉习性、主干通直度和保存率等6个性状的方差分析,并估算出6个性状的遗传相关和遗传力及指数选择等遗传参数。结果表明:无性系和地点的交互作用除了主干分叉习性有显著差异(p0.05)外,其他性状在无性系间差异均极显著(p0.001)。当不考虑无性系和地点互作时,无性系间不同性状的重复力均较高,为0.35 0.85,其中,树高重复力最高,主干分叉习性最低。遗传相关分析结果表明:树高、胸径、单株材积和保存率之间的表型及遗传存在极显著的正相关。树高、胸径、单株材积、主干分叉习性、主干通直度和保存率的平均遗传增益分别为6.5%、4.8%、10.9%、3.7%、1.5%和8.1%,筛选可获得明显的遗传增益。通过Smith-Hazel指数选择并按20%的入选率,选育出编号17、21和20三个优良无性系。     

尖峰岭绿楠树生长过程的研究

对海南尖峰岭地区３０年生的热带乡土树种———绿楠人工林进行了样地调查,并进行了样木横剖树干解析,研究其生长规律及与环境的关系。研究结果表明：（１）绿楠是比较速生的树种,地径、胸径、树高和材积的年生长都呈多峰态曲线;（２）胸径年生长高峰值出现在第１１年,而树高年生长量高峰期晚于地径和胸径生长高峰值出现的年份;（３）在生长初期（８ａ前）,材积生长极缓慢,年生长量＜００００９ｍ３,其后开始较快增长,到第１７年出现最大值０００８６８ｍ３;（４）从平均生长量看,地径变化比较平缓;胸径在１４ａ前呈稳态上升趋势,１４ａ后呈平稳发展状态并略有下降;树高在１９ａ前基本呈稳态上升趋势,１９ａ后保持在０５０ｍ／ａ左右,并呈缓慢地下降趋势;材积一直是随着年龄的增加而增加;（５）不同坡位的水肥等条件不同,因而影响了绿楠树的生长,离水沟最近的下坡地的树高和胸径比上坡分别大３７５％和２９１％;（６）绿楠树地径、胸径和树高的连年生长变化趋势基本上与降雨蒸发比（Ｒ／Ｅ）变化趋势相一致,说明水分状况是影响绿楠生长的一个重要环境因子。     

Models for Predicting Dry Matter Content of Norway spruce

Models were developed for predicting the dry matter content of single Norway spruce [Picea abies (L.) Karst.] stems from non-destructive field measurement data such as tree height, diameter and age. The material under study comprised 1612 stem discs originating from 235 trees grown at nine locations in Denmark and southern Sweden. In total, 153 trees (1054 discs) originating from a thinning experiment in southern Denmark were used for establishing the models, which were later validated on independent material. Results of the validation were that the 95% confidence interval for single stem density was ±9 to ±16% when based on average ring width at breast height, but within ±7% when based on wood samples taken at breast height. The density models were combined with standard volume models in order to predict dry matter content. Validation on independent material showed that in general the dry matter content of single stems can be estimated with less than 10% error (RMSE).     

Growth Variation and Early Selection of Betula Platyphylla in Natural Stands

IntroductionEarlyseIectionisanimportantpartforforesttreeim-provement.TreequaIityandproductioncanbeim-provedthroughselection.lnrecentyears,wehavepaidmoreattentiontoearlyselectionandprediction.EarIyselectionisanimportantpartforforesttreeimprove-ment.Thegene…     

白桦树干导管特征的轴向和径向变化

为探明白桦树干导管特征的分布情况,由髓心向树皮逐年轮测定10株解析木树干不同高度的导管直径、管孔密度和导管组织比量。结果表明:随树干高度增加,导管直径减小,管孔密度和导管组织比量增加。由髓心向树皮,导管直径先迅速增加,在达到某一年龄后(伐根处20 a,胸径处15 a,枝下高处10 a)趋于平稳;管孔密度在伐根处基本以线性递减,在胸径处和枝下高处是先迅速减少,然后分别在15 a和10 a后趋于平稳;导管组织比量略有降低。这些结果表明白桦导管特征在树干内的分布具有空间差异。     

Photogrammetric measurement of tree stems from vertical fisheye images

Forest variables are typically surveyed using sample plots, from which parameters for large areas are estimated. The diameter at breast height (DBH) is one of the main variables collected in the field and can be used with other forest measures. This study presents an automatic technique for the mapping and measurement of individual tree stems using vertical terrestrial images collected with a fisheye camera. Distinguishable points from the stem surface are automatically extracted in the images, and their 3D ground coordinates are determined by bundle adjustment. The XY coordinates of each stem define an arc shape, and these points are used as observations in a circle fitting by least squares. The circle centre determines the tree position in a local reference system, and the estimated radius is used to calculate the DBH. Experiments were performed in a sample plot to assess the approach and compare it with a technique based on terrestrial laser scanning. In the validation with measurements collected on the stems using a measuring tape, the discrepancies had an average error of 1.46?cm with a standard deviation of 1.09?cm. These results were comparable with the manual measurements and with the values generated from laser point clouds.     

江西金盆山林区米槠生长过程与幼林生长效应

进行样地调查与树干解析,以研究米槠生长过程。采用米槠容器苗和裸根苗造林,比较造林保存率、胸径、树高、冠幅、变异系数等指标,以了解两种苗木的幼林生长效应,并比较天然林与人工林米槠的早期生长。研究表明,米槠在10-20 a,树高、胸径生长较快;14-30 a,材积生长较快;树龄33 a时,尚未达到数量成熟阶段。米槠容器苗造林的保存率、胸径、树高值均大于裸根苗,其中保存率比裸根苗高9.5%,胸径值大11.3%,树高值大4.6%。比较人工林和天然林的早期生长,人工林树高和胸径值均大于天然林。米槠容器苗造林,可以促进米槠生长,取得较好的造林效果。     

A flexible stem taper and volume prediction method based on mixed-effects B-spline regression

Modelling stem taper and volume is crucial in many forest management and planning systems. Taper models are used for diameter prediction at any location along the stem of a sample tree. Furthermore, taper models are flexible means to provide information on the stem volume and assortment structure of a forest stand or other management units. Usually, taper functions are mean functions of multiple linear or nonlinear regression models with diameter at breast height and tree height as predictor variables. In large-scale inventories, an upper diameter is often considered as an additional predictor variable to improve the reliability of taper and volume predictions. Most studies on stem taper focus on accurately modelling the mean function; the error structure of the regression model is neglected or treated as secondary. We present a semi-parametric linear mixed model where the population mean diameter at an arbitrary stem location is a smooth function of relative height. Observed tree-individual diameter deviations from the population mean are assumed to be realizations of a smooth Gaussian process with the covariance depending on the sampled diameter locations. In addition to the smooth random deviation from the population average, we consider independent zero mean residual errors in order to describe the deviations of the observed diameter measurements from the tree-individual smooth stem taper. The smooth model components are approximated by cubic spline functions with a B-spline basis and a small number of knots. The B-spline coefficients of the population mean function are treated as fixed effects, whereas coefficients of the smooth tree-individual deviation are modelled as random effects with zero mean and a symmetric positive definite covariance matrix. The taper of a tree is predicted using an arbitrary number of diameter and corresponding height measurements at arbitrary positions along the stem to calibrate the tree-individual random deviation from the population mean estimated by the fixed effects. This allows a flexible application of the method in practice. Volume predictions are calculated as the integral over cross-sectional areas estimated from the calibrated taper curve. Approximate estimators for the mean squared errors of volume estimates are provided. If the tree height is estimated or measured with error, we use the “law of total expectation and variance” to derive approximate diameter and volume predictions with associated confidence and prediction intervals. All methods presented in this study are implemented in the R-package TapeR.