全站仪测树中材积模型选择

随着新型测树方法的出现,可直接获取的测树因子种类也越来越多.为研究不同树高处直径因子代替胸径因子建立材积模型的可能性,使用全站仪分别测量263株木棉树地径、胸径、树高1/3高处直径、树高1/2处直径,以回归分析的方式建立一元和二元材积模型.结果表明,对于同变量构建的模型,二次曲线、复合曲线、幂函数、指数函数模型的拟合结...     

杂种落叶松大径材优良家系选择

以材积生长量为主要指标,对27年生杂种落叶松进行优良家系初步选择,并初步探讨了树高、胸径、中央直径及其相互作用对材积生长量的影响,进而找出影响材积生长的主要因子。研究表明,中央直径是影响材积的主要性状,性状对材积的影响依次为中央直径〉胸径〉树高。胸径与中央直径的相关较紧密,而胸径与树高、中央直径与树高的相关不同家系表现各异。     

尾叶桉造林密度试验

尾叶桉4种不同造林密度试验结果表明:从造林后的第2年开始,不同密度的林木胸径、树高、单株材积和生物量(鲜重)都随密度的减小而增大,且经方差分析均达到极显著水平.4年生时最小密度的林木胸径、树高、单桉材积和生物量分别是最大密度的1.70倍、1.31倍、3.43倍和3.36倍.     

马尾松采脂林胸径破坏致材积测量误差的修正

经进行调查和试验表明，用马尾松采脂林被割胸径的测量值和树高，查符合精度要求的二元材积表，所得材积相对误差高达３０％以上．为此，在分析修正误差可能途径的基础上，研究了干基不同高度直径与胸径的相关关系，并建立了相关模型．结果表明，距地面１０ｃｍ，１５ｃｍ和２０ｃｍ处的干基直径与胸径的关系极为紧密．根据Ｄ１．３—Ｄ０．１０，Ｄ１．３—Ｄ０．１５和Ｄ１．３—Ｄ０．２０相关模型修正的胸径测量材积，在可靠性为９５％时，精度均可达到９７％以上．     

福建省杉木人工林立木相容性生物量模型的研究

在福建省不同年龄、立地、密度并且生长正常的杉木人工林中采集生物量样木218株,利用SPSS统计分析软件,采用胸径与树高或者二者的组合作为生物量模型的自变量,考虑材积因子的影响,选定W=f(D,H)·V作为生物量模型的一般结构形式。采用二级非线形模型联合估计的方法解决总量与分量模型不相容的问题,构建杉木人工林立木相容性生物量模型,为福建省杉木人工林碳汇能力的计算提供参考。     

刺槐树冠生物量估测模型的研究

利用３５株刺槐生物量资料，运用灰色关联分析法，对其不同部位直径及各立木因子对树冠生物量的影响进行分析，筛选出影响树冠生物量的主导因子。通过对一系列估测树冠生物量模型的比较，得出以胸径和冠幅为自变量的回归估测模型比单用胸径因子为自变量的估测模型明显地提高了估测精度。     

东北林区典型树种内部心腐材积的量化检测

为分析活立木心腐材积损失变化规律及材积与胸径的关系,利用Arbotom应力波测试仪对带岭凉水国家自然保护区内红松(Pinus koraiensis)、旱柳(Salix matsudana)、山杨(Populus davidiana)、水曲柳(Fraxinus mand-schurica Rupr.)等4种活立木不同高度处144个断面的腐朽状况进行检测,获取每个断面的树干直径和应力波断层图像。根据应力波断层成像,筛选出存在心腐的断面共78个,利用Envi 5.0最大似然法对心腐断面进行分类并计算断面腐朽面积,据此模拟出活立木内部腐朽的立体模型,然后通过分区段求材积法估算其腐朽材积。在此基础上,对活立木心腐材积变化规律及材积与胸径的关系进行统计分析。结果表明:活立木心腐面积随高度的增加呈递减趋势;活立木心腐材积与胸径之间存在显著的正相关性(R=0.618,P=0.0000.01),胸径越大,活立木心腐材积比例也增大。     

福建省火炬松造林密度试验

在火炬松世行造林试验中,设计了4种密度,结果表明,不同密度对火炬松6年生林分的树高无显著影响,对6年生火炬松的胸径、材积、蓄积的影响达显著水平,对14年生火炬松的树高、胸径、材积、蓄积的影响均达极显著水平；不同密度、林龄火炬松各器官生物量的分配规律为：树干＞树根＞树枝＞树叶,各器官生物量的分配比例相对稳定。     

闽粤栲人工林生物量研究

利用树干解析计算分析福建省牛姆林自然保护区22年生闽粤栲人工林的生长量、生物量及生产力特征.结果表明:闽粤栲树高、胸径和材积总生长量分别达到16.5 m,19.5 cm和0.27 m3,期间分别出现3次、5次和2次生长高峰,其中,树高和胸径生长高峰出现年份一致,材积生长高峰出现相对滞后;树高、胸径连年生长量曲线与平均生长量曲线出现多次相交,材积各生长量曲线基本不相交且变化幅度相对较小;将闽粤栲树高、胸径和材积总生长量与林龄进行回归方程拟合,拟合效果理想;闽粤栲各器官生物量表现为干＞枝＞根＞叶,各器官含水率表现为根＞干＞枝＞叶,单株平均含水率为48.05％;闽粤栲种群生物量为295 261 kg/hm2,种群净生产力为13 420.95 kg/(hm2 ·a).     

含地域和起源因子的马尾松立木生物量与材积方程系统

【目的】建立含地域和起源因子的相容性立木生物量与材积方程系统,为准确估计森林生物量提供依据。【方法】以我国南方主要针叶树种马尾松为研究对象,基于301和104株样木的实测地上生物量、树干材积和地下生物量数据,综合利用哑变量建模方法和误差变量联立方程组方法,建立集地上生物量、树干材积和地下生物量为一体、确保与生物量转换因子和根茎比等变量相容的一元和二元方程系统,并分析立木生物量和材积估计是否受地域和起源的影响。【结果】所建立的马尾松一元和二元相容性立木生物量方程与材积方程,确定系数(R~2)均在0.92以上,其中地上生物量方程的平均预估误差在4%以内,地下生物量方程的平均预估误差在8%以内。对马尾松地上生物量和树干材积的估计,二元模型均显著优于一元模型,其F统计量远大于临界值;但对地下生物量的估计,二元模型反而不如一元模型效果好。不论是一元模型还是二元模型,地域和起源对马尾松地上生物量估计均无显著影响,地上生物量模型具有很好的通用性,同时也进一步印证了曾伟生等(2012)提出的通用性地上生物量模型M=0.3ρD~(7/3)的广泛适用性。对马尾松地下生物量的估计,不同地域的模型存在显著差异;相同直径的林木,总体1地域范围内(长江流域东南部)的地下生物量要大于总体2(长江流域中西部)。对马尾松树干材积的估计,二元模型不受地域和起源影响,但一元模型受起源影响;相同直径的林木,人工林的材积估计值大于天然林。【结论】将哑变量引入误差变量联立方程组,可同时解决多个变量之间的相容性及地上生物量和地下生物量样本单元数不相等时如何联合建模的问题,是切实可行的生物量建模方法;研究所建立的马尾松立木生物量方程、材积方程及其相容的生物量转换因子和根茎比方程,达到相关技术规定预估精度要求,可推广应用。     

林木竞争对臭冷杉生物量分配的影响

用不同高度树干直径建立并比较臭冷杉各器官生物量方程,分析林木竞争对臭冷杉地上、地下生物量分配的影响。结果表明:臭冷杉不同高度树干直径中,胸径是预测各器官生物量的最可靠变量;利用不同高度树干直径建立各器官生物量方程均会高估小个体样木(直径≤10cm)的生物量,并且随着直径增大,预测误差也随之增大;臭冷杉地上生物量与地下生物量的比值(T/R)与树木年龄、单株生物量、整株生物量年均生长率及树高年均生长率间均没有显著相关性(P>0.05);随着竞争增强,臭冷杉树干生物量占单株生物量的比例逐渐减小,枝叶生物量比例逐渐增大,而粗根生物量比例则基本保持不变;胸径年均生长率、树高年均生长率及单株生物量年均生长率均随着竞争强度增大逐渐减小,而T/R值并不受林木竞争的影响。     

全国立木生物量建模总体划分与样本构成研究

结合全国生态地理区域和行政区域,并兼顾立木材积表的建模总体划分,提出了全国立木生物量建模总体划分方案,将全部树种分为34个树种组,全国分为6大地理区域,共划分70个建模总体;通过对已有立木生物量数据进行建模分析,将立木生物量模型的预估精度确定为95%以上,同时根据变动系数分析结果提出合适的建模样本单元数应该在150以上,且要按划定的10个径阶均匀分配,保证每个径阶的样本单元数不少于15个;以第七次全国森林资源清查数据为基础,确定了每一个建模总体的样本结构,将样本单元数全部落实到了各省和各级径阶。研究成果可为推进全国森林生物量调查建模工作提供参考依据。     

Crown area allometries for estimation of aboveground tree biomass in agricultural landscapes of western Kenya

Classical allometries determine biomass from measurements of diameter at breast height or volume. Neither of these measurements is currently possible to be derived directly from remote sensing. As biomass estimates at larger scales require remotely sensed data, new allometric relations are required using crown area and/or tree height as predictor of biomass, which can both be derived from remote sensing. Allometric equations were developed from 72 trees semi-randomly selected for destructive sampling in three 100?km² sentry sites in western Kenya. The equations developed fit the data well with about 85?% of the observed variation in aboveground biomass explained by crown area. Addition of height and wood density as second predictor variables improved model fit by 6 and 2?% and lowered the relative error by 7 and 2?%, respectively. The equation with crown area in combination with height and wood density estimated representative aboveground biomass carbon to be about 20.8?±?0.02?t?C?ha^?1; which is about 19?% more than the amount estimated using an allometry with diameter at breast height as predictor. These results form the basis for a new generation of allometries using crown area as a predictor of aboveground biomass in agricultural landscapes. Biomass predictions using crown area should be supported by height and wood density and the application of crown area equations for remote sensing based up-scaling should consider crown interactions with competing or coexisting neighboring trees.     

Volume equations and biomass estimates for three species in tropicalmoist forest in the Orientale province,Democratic Republic of Congo

Volume equations predict the volume of the stem of a tree from dendrometrical characteristics that are easy to measure, such as diameter and/or height. These equations can serve as a surrogate for biomass equations, by converting the stem volume to stem biomass, and then expanding it to the total aboveground biomass. This is especially important for Central Africa where biomass equations are scarce, whereas volume equations are common. We measured the stem volume of 459 trees in the Yoko forest, Orientale province, Democratic Republic of Congo. These trees belonged to three species: Gilbertiodendron dewevrei (limbali), Guarea thompsonii (bossé foncé) and Scorodophloeus zenkeri (divida). Species-specific volume equations were fitted using these data, and biomass estimates were derived from these volume equations. The fitted volume equations were consistent with other location-specific volume equations for the same species. The biomass estimates derived from the fitted volume equations were also found to be consistent with multispecies pantropical biomass equations.     

Development of equations for predicting Puerto Rican subtropical dry forest biomass and volume

Carbon accounting, forest health monitoring and sustainable management of the subtropical dry forests of Puerto Rico and other Caribbean Islands require an accurate assessment of forest aboveground biomass (AGB) and stem volume. One means of improving assessment accuracy is the development of predictive equations derived from locally collected data. Forest inventory and analysis (FIA) measured tree diameter and height, and then destructively sampled 30 trees from 6 species at an upland deciduous dry forest site near Ponce, Puerto Rico. This data was used to develop best parsimonious equations fit with ordinary least squares procedures and additive models fit with nonlinear seemingly unrelated regressions that estimate subtropical dry forest leaf, woody, and total AGB for Bucida buceras and mixed dry forest species. We also fit equations for estimating inside and outside bark total and merchantable stem volume using both diameter at breast height (d.b.h.) and total height, and diameter at breast height alone for B. buceras and Bursera simaruba. Model fits for total and woody biomass were generally good, while leaf biomass showed more variation, possibly due to seasonal leaf loss at the time of sampling. While the distribution of total AGB into components appeared to remain relatively constant across diameter classes, AGB variability increased and B. simaruba and B. buceras allocated more carbon into branch biomass than the other species. When comparing our observed and predicted values to other published dry forest AGB equations, the equation developed in Mexico and recommended for areas with rainfall >900 mm/year gave estimates substantially lower than our observed values, while equations developed using dry forest data from forest in Australia, India and Mexico were lower than our observed values for trees with d.b.h. <25 cm and slightly higher for trees with d.b.h. >30 cm. Although our ability to accurately estimate merchantable stem volume and live tree AGB for subtropical dry forests in Puerto Rico and other Caribbean islands has been improved, much work remains to be done to sample a wider range of species and tree sizes.     

Integrated individual tree biomass simultaneous equations for two larch species in northeastern and northern China

Forest biomass estimation at large scale has become an important topic in the background of facing global climate change, and it is fundamental to develop individual tree biomass equations suitable for large-scale estimation. Based on the measured data of biomass components and stem volume from 100 sample trees of two larch species (Larix gmelinii and L. principis-rupprechtii) in northeastern and northern China, an integrated equation system including individual tree biomass equations, stem volume equation and height–diameter regression model were constructed using the dummy variable model and error-in-variable simultaneous equations. In the system, all the parameters of equations were estimated simultaneously, so that the aboveground biomass equation was compatible to stem volume equation and biomass conversion factor (B_CF) function; the belowground biomass equation was compatible to root-to-shoot ratio (R_SR) function; and stem wood, stem bark, branch and foliage biomass equations were additive to aboveground biomass equation. In addition, the system also ensured the compatibility between one- and two-variable models. The results showed that: (1) whether aboveground biomass equations or belowground biomass equations and stem volume equations, the estimates for larch in northeastern China were greater than those in northern China; (2) B_CF of a larch tree decreased with the growing diameter while R_SR increased with the growing diameter; (3) the proportion of stem wood biomass to aboveground biomass increased with the growing diameter while those of stem bark, branch, and foliage biomass decreased.     

Comparison of Forest Biomass Across a Human-Induced Disturbance Gradient in Nepal's Schima-CastanopsisForests

Abstract

This paper presents estimations of aboveground tree biomass (combined for boles and branches) in Nepal's Schima-Castanopsisdominated warm-temperate forests. The biomass estimations are presented for five forest stands purposively sampled in a larger study to represent different harvesting intensities. Two categories of biomass estimates are provided: (1) for living trees that are standing, and (2) for cut trees that have been removed. Biomass of standing trees were estimated by using diameter at breast height (dbh) and total height measurements as predictor variables in appropriate regression models. Biomass of cut trees were estimated in two steps: measurements of stump diameters and heights were used first to predict dbh and total heights of cut trees; these values were then regressed to obtain biomass estimates for the missing trees. Data were gathered from 2,361 live trees and 2,962 stumps in 170 sample plots across the five forest stands. Estimates of mean standing-alive biomass ranged from a minimum of 16 ton/ha in the severely disturbed forest to a maximum of 479 ton/ha in a relatively undisturbed (reference) forest. Estimates of mean cut biomass ranged from a minimum of 24 ton/ha in a second reference forest to a maximum of 183 ton/ha in the severely disturbed forest. The biomass estimates in the relatively-undisturbed, reference forests are well above the 95% upper confidence interval of the global mean. Similar findings of high productivity have been reported for temperate forests of the Central Himalaya in India and Eastern Himalaya in Sik-kim. The findings of this study in the Nepalese Central Himalaya support the conclusion that productivity potential is high in the temperate Himalayan forests. The study's findings and methodology should be useful for preliminary development of guidelines in the region to regulate forest biomass growth, yield, and harvest.     

Distribution of biomass and carbon in even‐aged stands of Norway spruce (Picea abies (L.) Karst.): A case study on spacing and thinning effects in northern Denmark

The main objective of this case study was to explore the possible influence of forest management on the levels and distribution of biomass and carbon (C) in even-aged stands of Norway spruce [Picea abies (L.) Karst.] in Denmark. Data originated from a long-term thinning experiment and an adjacent spacing experiment at stand ages of 58 and 41 years, respectively. Biomass of 16 trees from different thinning and spacing treatments was measured or partly estimated, and soils were sampled for determination of C stocks. All trees in each plot were measured for stem diameter and some for total height, to allow for scaling-up results to stand-level estimates. For trees of similar size, foliage biomass tended to be higher in the spacing experiment, which was located on slightly more fertile land. Foliage biomass increased with increasing thinning grade, but the effect could not be separated from that of tree size. At stand level, foliage biomass tended to increase with increasing spacing as well as with increasing thinning grade. For branchwood, stems and roots (including below-ground stump), the biomass increased with increasing tree size and stand volume at tree and stand level, respectively, but no differences between stands, spacings or thinning grades were observed, apart from that expressed by tree size or stand volume. At stand level, C stocks of all biomass compartments decreased with increasing thinning grade, while the distribution between compartments was hardly influenced. The ratio between above-ground and stem biomass was about 1.21 at stand level, while the ratio between below- and above-ground biomass was about 0.17. Thinning influenced the C stock of the forest floor and mineral soil oppositely, resulting in no effect of thinning on total soil C.     

Allometric estimation of above-ground biomass and leaf area in managed Grevillea robusta agroforestry systems

Non-destructive methods for determining the biomass and leaf area of individual trees throughout their growing cycle are an essential tool in agroforestry research, but must be capable of providing reliable estimates despite the influence that management strategies such as pruning may have on tree form. In the present study, allometric methods involving measurements of the diameter of all branches provided reliable estimates of canopy leaf area and biomass for grevillea trees (Grevillea robusta A. Cunn.; Proteaceae) grown as poles, but proved unsuitable for routine measurements because of their time-consuming nature. An alternative, less laborious method based on measurements of trunk cross-sectional area immediately below the first branch of the canopy provided satisfactory allometric estimates of leaf area and canopy biomass. Trunk biomass was determined from measurements of tree height and diameter at breast height using established methodology based on the assumption that trunk volume may be calculated using a quadratic paraboloid model; biomass was determined as the product of trunk volume and the specific gravity of the wood. The theoretical basis, development and validation of allometric methods for estimating tree growth are discussed and their wider applicability to other agroforestry systems is assessed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Biomass, basic density and biomass expansion factor functions for European beech (Fagus sylvatica L.) in Denmark

The objective of this study was to analyse the within-tree allocation of biomass and to develop biomass functions for above- and below-ground components of European beech in Denmark. Separate functions were developed for stem, branches, below-ground stump and root system, total above-ground biomass and total tree biomass. For each of these components or aggregate components, models were also developed for the average basic density of wood and bark. To enhance the versatility of the models, a function for estimating the biomass expansion factor (BEF) was also developed. The functions were based on 66 trees measured for total biomass. Model performance was evaluated based on 74 trees measured only for above-ground biomass. The trees were sampled in 18 different forest stands covering a wide range of tree sizes and stand treatments. Models were estimated using a linear mixed-effects procedure to account for within-stand correlations. The functions for biomass and BEFs included only diameter at breast height and total tree height for individual trees as predictor variables. Inclusion of additional variables reflecting site quality or stand density did not improve model performance. The functions for basic density included individual tree diameter, tree height and quadratic mean diameter as predictor variables, indicating an effect of stand density on the basic density of wood and bark.