兴安落叶松树干去皮直径预测模型

利用兴安落叶松解析木数据,比较了树干去皮直径预测的3种类型模型:Grosenbaugh的比率方程式、回归模型和削度方程。Grosenbaugh的比率方程式有很大的灵活性,没有参数不需要模型拟合。总体评价和模型分段比较表明,回归模型有较小的预测误差,尤其是Cao and Pepper提出的含有带皮直径、树高、相对树高、胸径处的带皮直径和去皮直径变量的模型。由于削度模型不含有带皮直径变量,因此产生较大的去皮直径预测误差。不同类型的模型在森林经营过程中都有一定的适应性。     

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Abstract

The volume of bark is a function of bark thickness and tree diameter, thus bark and tree volume calculations depend on accurate determination of bark thickness. Bark thickness is affected by a number of inherent and external factors. The purpose of this study was to examine the factors affecting bark thickness and to derive models predicting bark thickness for Picea orientalis (L.) Link. This study indicated that bark thickness at breast height was strongly correlated with geographical aspect, tree age and diameter classes, and bark thickness increased as tree age or diameter class increased in sunny or shady aspect. Diameter over bark at breast height explained 50% of the variations in double bark thickness at breast height on shady aspects and 68% of the variations in double bark thickness of P. orientalis at breast height on sunny aspects. By adding tree age to the functions, the coefficient of determination increased by 1–2%. Thus, not only tree ages and diameters, but also the aspect in which trees grow should be taken into account to calculate the amounts of wood and bark in P. orientalis.     

基于哑变量的湿地松树皮厚度模型研究

拟合立地质量等级的湿地松树皮厚度模型,为测算生长于不同立地湿地松出材量、出材率及树皮材积提供依据。根据宁德市湿地松样木和样地的调查数据,运用R软件拟合4类树皮厚度模型,选用赤池信息准则(AIC)、贝叶斯准则(BIC)、偏差(B)、绝对偏差(AB)与决定系数(R2)为模型评价指标,使用含熵权值的TOPSIS法筛选最优模型,于得到的4类树皮厚度最优模型中加入立地质量等级哑变量,得到胸高处树皮厚度模型lnTBB=(-3.075S1-3.154S2-3.157S3-3.325S4)+1.125lnD1.3,任意高度处树皮厚度模型TB=(0.005S1-0.026S2-0.101S3-0.141S4)-0.616RC+0.761DR+0.040dob,相对树皮厚度模型TRB=0.137+0.903DR2.009S1+1.806S2+2.126S3+1.855S4,去皮直径模型dib=(-0.087S1+0.138S2+0.223S3+0.293S4)+0.881dob,这4个哑变量模型R2相对于原模型分别提升了8.9%、41.6%、20.4%和1.2%,各项低优指标均降低,经配对t检验,4个哑变量模型的预估值与实测值不存在明显差异,比原模型拟合效果更佳。     

Comparison of models for estimating bark thickness of <Emphasis Type="Italic">Picea abies</Emphasis> in southwest Germany: the role of tree,stand, and environmental factors

Key message

Bark thickness was shown to vary between regions, stands, and trees. Bark thickness prediction equations of different model complexity can be suggested depending on the purpose of application. Site and stand conditions, which influence variation of growth rate to a large extent, seem to have a strong influence on bark thickness, with better site quality leading to smaller relative bark thickness.

Context

For many applications in forestry and forest science, local or regional species-specific bark thickness equations are used to estimate inside-bark diameters with outside-bark diameter measurements.

Aims

The objectives of this study were (1) to assess variation in bark thickness due to tree and stand factors in two Norway spruce (Picea abies (L.) Karst) datasets from different time periods, (2) to compare and evaluate alternative established model forms for estimating bark thickness, and (3) to assess spatial variation in bark thickness to estimate the effects of environmental factors on bark thickness.

Methods

Different bark thickness models were chosen from the literature and compared for their predictive quality for new measurements and a dataset from the 1970s. Mixed-effect modelling was applied to account for the hierarchical data structure, and generalized additive mixed models were used to analyse spatial effects and the influence of climatic factors, such as precipitation and temperature.

Results

A strong positional autocorrelation of bark thickness within trees and within plots could be shown. Bark thickness was smaller in the new data compared to the measurements from the 1970s. The variation between stands could not be explained by the tested environmental factors, but tree age had a strong positive effect on bark thickness.

Conclusion

In the study region, the variation of site productivity and individual growth rate seem to have a strong influence on bark thickness, whereas no significant effect of large scale climatic factors could be found.

     

Improving harvester estimates of bark thickness for radiata pine (Pinus radiata D.Don)

Harvesters estimate bark thickness primarily from diameter over bark (DOB) and use it to estimate log volume and value. Harvester bark thickness estimation errors can reduce returns through poor bucking optimisation and out-of-specification logs. Radiata pine bark thickness data from harvested logs and permanent sample plots (PSP) were analysed to determine best-fit coefficients for current and potential future harvester bark thickness models. The most suitable current harvester bark thickness model for radiata pine is: double bark thickness = b ₀ + b ₁*DOB (the ‘DOB model’). This describes a straight line, whereas radiata pine bark relative to DOB is thicker near the stem base and consistent over the remainder. PSP data set coefficients for this model overestimated upper stem bark thickness and underestimated lower stem values. The harvester model for Scots pine bark fitted better than the DOB model for diameters <400 mm but performed poorly for larger logs, as it is restricted to trees with a diameter at breast height <590 mm. Two better models were identified: (1) a model using relative height to account for bark thickness changes with height, and (2) implementing separate DOB models for the bottom 10% and top 90% of the stem split by relative height. These approaches require approval by the StanForD committee to be implemented. Prior to approval, the upper 90% model coefficients could be applied to the entire stem to improve upper 90% stem volume and value predictions at the expense of the lower 10%. Further research will determine if this approach produces acceptable results when optimising bucking. Increasing variability of bark thickness estimates with increasing DOB in the PSP data set may reflect manual measurement errors with thicker bark or may show that additional explanatory variables are needed. Efforts to identify new variables would need to be weighed against additional returns and probable reductions in numbers of larger trees by as the clearfell age is reduced.     

Variations in bark thickness and sapwood density of <Emphasis Type="Italic">Calophyllum inophyllum</Emphasis> provenances in Australia and in Sri Lanka

Sapwood density and bark thickness of Calophyllum inophyllum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4-15 mature trees having girth at breast height over bark (GBHOB) at 100-150 cm were selected on the basis of the population size. Significant (p<0.05) hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.     

尾巨桉树皮率及树皮纤维尺寸的变异研究

以广西贵港市平天山林场5年生、6年生和7年生的尾巨桉为对象,分析了不同树龄尾巨桉的树皮率和树皮纤维尺寸的株内变异特性。结果表明:尾巨桉的体积树皮率和重量树皮率均随着树干高度的增加而逐渐减小。树皮纤维长度随着树干高度的增加略有增加,但变化幅度不大;树皮纤维宽度、双壁厚度和壁腔比均随树干高度的增加而减小;树皮纤维长宽比则随树干高度的增加而增加。方差分析表明,不同树龄间尾巨桉树皮纤维长度和长宽比差异极显著,壁腔比差异不显著。     

Growth and yield of some indigenous trees in an Amazonian agroforestry system: a rural-history-based analysis

Over the years farmers of Japanese descent in the Brazilian Amazon have planted indigenous trees that yield various products and services: fruit, seeds,bark, latex, oil, and shade and wind breaks for understory crop plants. Production of timber is often the intended end use of such planted trees. Long-term growth performance of these trees nevertheless has not been well documented. The authors constructed 65-year growth curves for nine indigenous tree species based on measurements of diameter at breast height (dbh), height, and tree age data provided by farmers in the Brazilian State of Pará. An index of wood prices used to calculate state stumpage taxes was then applied to mean stem wood growth curves to produce price curves. These price curves estimate both present value of standing timber, and the value added from annual growth of standing timber in the agroforestry systems studied. The results of this study provide local farmers with a tool to estimate potential annual income from the growth of their trees, and a basis for planning timber harvest rotations. This study's approach may be applicable in other parts of the tropics, where growth information about indigenous trees commonly used in agroforestry is lacking.This revised version was published online in November 2005 with corrections to the Cover Date.     

树高、胸径、树皮厚对厚朴产量的影响

为研究厚朴树高、胸径和树皮厚度对其产量的影响,从而为厚朴品种选优及丰产栽培提供理论指导。采用系统抽样方法抽取了10~14 a的90个厚朴单株样本,测量其单株树高、胸径、树皮厚和树皮产量,通过建立和分析厚朴产量回归方程可知,胸径、树高和树皮厚与产量均成正相关关系;胸径、树高、树皮厚对产量的直接影响从大到小依次为胸径、树高、树皮厚,其中胸径对产量的影响以直接影响为主,树高对产量的间接影响稍高于直接影响,其间接影响主要是通过胸径对产量产生影响,树皮厚主要通过胸径和树高对产量产生间接影响,直接影响较小。     

The implication of using a fixed form factor in areas under different rainfall and soil conditions for Pinus kesiya in Zambia

The study was undertaken to evaluate form factors for Pinus kesiya growing in the three Zambia Forest and Forestry Industries Corporation (ZAFFICO) plantations – the Ndola, Ichimpe and Chati groups – under different rainfall (900–1 500?mm) and soil conditions (pH 4.0–5.5). Trees were sampled from the three plantation groups and 10 sample plots were established in which 10 trees were randomly sampled for cutting. Height and diameter at breast height (dbh) were the main variables that were measured and constituted the collected data. The trees were then felled and cut into segments of 0.5?m from the bottom to the top of the tree and segment diameters over bark were measured at both ends. The form factor for each tree was then calculated by dividing the sum of the volume of the tree segments by the estimated cylindrical volume of the standing tree. The results showed significant differences (p-value<0.05) in form factors among the three plantation groups. The study further showed a significant difference in form factor when the three plantation groups were compared with a fixed form factor (0.4) used by ZAFFICO plantations, indicating that the form factors are site specific. Therefore, for the benefit of customers and plantation owners, it is important that area-specific form factors should be used for each plantation group, as these groups are affected by different factors such as soils characteristics and rainfall, which have a direct effect on the form factor.     

三江平原丘陵区长白落叶松人工林立木材积表的编制

以三江平原丘陵区佳木斯市孟家岗林场的长白落叶松人工林为研究对象,进行根径（D0.0）、去皮胸径（D去）、树高（H）同胸径（D）关系的研究,结合解析木结果,建立一元和二元立木材积模型、根径立木材积模型和树皮材积模型。结果表明,长白落叶松胸径是根径的0.730 7倍,去皮胸径是带皮胸径的0.942 7倍,树高模型为H=121.0-13 754.9/（D＋116.6）;一元和二元立木材积（V）模型分别为V=0.000084738D2.7516和V=0.000 03D1.88737H1.19248,根径立木材积（V）模型为V=0.0002D0.022652;一元和二元树皮材积（V皮）模型分别为V皮=0.000051724D2.1911和V皮=0.000 059D2.311560H-0.163587。     

凹叶厚朴生长与立地因子关系研究

通过对标准地的调查,运用逐步回归分析与通径相关分析方法,分别对凹叶厚朴树高、胸径、冠幅、树皮厚度、枝下高与立地因子的关系进行了分析研究。结果表明：影响凹叶厚朴树高、胸径、冠幅的主导因子是海拔和坡向,在适生区内海拔越高越不利于凹叶厚朴的生长,坡向以阳坡生长最好;坡位对凹叶厚朴胸径生长量的影响达到显著水平,下坡位有利于胸径...     

Douglas-fir and western larch: chemical and physical properties in relation to Douglas-fir bark beetle attack

Frequency of Douglas-fir bark beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Scolytidae), attack on western larch (Lark occidentalis Nutt.) was negatively correlated with 3-carene content of the xylem oleoresin. Concentrations of all oleoresin volatiles from stem cores of standing trees were higher in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) than in western larch with the single exception of 3-carene. Successful brood production by the Douglas-fir bark beetle in standing trees of Douglas-fir but not western larch may therefore be explained, at least in part, by the high 3-carene content of western larch. Other differences between the species that might affect susceptibility to beetle attack include thinner phloem, higher phloem moisture content and larger diameter vertical resin ducts in western larch compared with Douglas-fir. Live standing western larch had no oleoresin exudation pressure, suggesting that this trait is not associated with resistance to attack by the Douglas-fir bark beetle in this species.     

Bark thickness and bark volume of Pinus patula in South Africa

In South Africa, tree volume tables and volume functions are usually based on the under bark stem volume. Many forest management studies, however, give the estimated over bark volume, in which case equations are required that estimate bark volume and possibly bark thickness as a function of DBH and tree height. This study deals with the evaluation of geographical regions and tree characteristics on bark thickness and bark volume of Pinus patula in South Africa.     

Spatial partitioning of biomass and diversity in a lowland Bolivian forest: Linking field and remote sensing measurements

Large-scale inventories of forest biomass and structure are necessary for both understanding carbon dynamics and conserving biodiversity. High-resolution satellite imagery is starting to enable structural analysis of tropical forests over large areas, but we lack an understanding of how tropical forest biomass links to remote sensing. We quantified the spatial distribution of biomass and tree species diversity over 4 ha in a Bolivian lowland moist tropical forest, and then linked our field measurements to high-resolution Quickbird satellite imagery. Our field measurements showed that emergent and canopy dominant trees, being those directly visible from nadir remote sensors, comprised the highest diversity of tree species, represented 86% of all tree species found in our study plots, and contained the majority of forest biomass. Emergent trees obscured 1–15 trees with trunk diameters (at 1.3 m, diameter at breast height (DBH)) ≥20 cm, thus hiding 30–50% of forest biomass from nadir viewing. Allometric equations were developed to link remotely visible crown features to stand parameters, showing that the maximum tree crown length explains 50–70% of the individual tree biomass. We then developed correction equations to derive aboveground forest biomass, basal area, and tree density from tree crowns visible to nadir satellites. We applied an automated tree crown delineation procedure to a high-resolution panchromatic Quickbird image of our study area, which showed promise for identification of forest biomass at community scales, but which also highlighted the difficulties of remotely sensing forest structure at the individual tree level.     

Wood properties of <Emphasis Type="Italic">Pericopsis mooniana</Emphasis> grown in a plantation in Indonesia

The relationships between growth characteristics and wood properties were investigated for a threatened species, Pericopsis mooniana, to promote the establishment of plantations of this species in the tropics. Growth characteristics (diameter and height) and stress-wave velocity (SWV) of trees were measured for 22-year-old P. mooniana trees planted in Indonesia. The trees were categorized into three groups, fast-growing, middle-growing, and slow-growing trees, to investigate the effect of growth rate on the wood properties. In addition, radial variation of anatomical characteristics and wood properties were determined. No significant correlation was found between growth characteristics and SWV. The values for the vessel diameter, cell wall thickness of wood fibers, wood fiber length, basic density, modulus of elasticity, and modulus of rupture from wood at the bark side were higher than those at the pith side. On the other hand, vessel frequency gradually decreased from pith to bark. These results suggested that low-quality wood, such as juvenile wood, existed near the pith area.     

Genetic control of wood density and bark thickness,and their correlations with diameter,in pure and hybrid populations of Eucalyptus grandis and E. urophylla in South Africa

Tree diameter under and over bark at breast height (dbh), wood density and bark thickness were assessed on samples from control-pollinated families of Eucalyptus grandis, E. urophylla, E. grandis × E. urophylla and E. urophylla × E. grandis. The material was planted in field trials in the coastal Zululand region of South Africa. At 75 months, between three and seven of the best trees per family were felled and wood samples collected. Genetic parameters for wood density, bark thickness and bark percentage (ratio of double bark thickness to overbark diameter) and the inter-trait correlations for the different species and hybrids were calculated. Genetic parameter estimates for wood density, bark thickness and bark percentage in the E. urophylla × E. grandis hybrids showed these traits to be under total additive genetic control. This was confirmed by the intermediate hybrid means for these traits relative to those of the parental species. There was a very low correlation between dbh and wood density for the E. urophylla × E. grandis hybrids (r_G = –0.07 and r_P = 0.064). Amongst the E. urophylla families there was a moderate positive and significant phenotypic correlation between wood density and bark thickness (r_P = 0.391), and between wood density and bark percentage (r_P = 0.442).     

兴安落叶松过伐林枯立木分布格局特征分析

以内蒙古根河林业局潮查林场境内的在20世纪80年代初主伐利用后形成的兴安落叶松过伐林为研究对象,利用兴安落叶松林8块标准地每木定位数据,分析林木分布格局和样方(5 m×5 m)林木株数对枯立木株数影响,探讨了林分大树和更新幼树位置与枯立木位置的关系,阐明了枯立木分布格局形成机制。结果表明:1)各树种枯立木比例,随树种组成成数增加而增大。枯立木主要在更新幼树阶段形成,径级分布集中在4径阶以下,其株数占总数的比例平均达82.2%。在更新幼树(含枯立木)中,生成枯立木的比例平均达8.8%。2)枯立木分布格局为聚集分布。林木分布格局、样方林木株数和更新株数与枯立木株数有显著正相关关系,林木分布格局对枯立木分布格局无显著影响。林木聚集度越大,形成枯立木的可能性越大,数量也就越多。3)枯立木位置与更新幼树和大树位置有显著相关关系。主要表现为落叶松和白桦相互关系。枯立木出现位置主要在大树和更新幼树集聚区域。大树对枯立木形成影响较更新幼树大,而且均以落叶松较白桦明显。白桦更新幼树对落叶松枯立木的形成,无显著影响。受影响的枯立木主要是枯立木株数中所占比例和树种组成成数较高的树种。影响枯立木位置的林木主要取决于其样方内位置和林木株数。     

Wood density,phytomass variations within and among trees,and allometric equations in a tropical rainforest of Africa

The development of tree allometric equations is crucial to accurate forest carbon assessment. However, very few allometric equations exist for sub-Saharan Africa and as a result generalized allometric equations, often established for forests in other continents, are used by default. The objectives of this study were (1) to propose a sampling methodology and calculation procedures to assess biomass for tropical tree species of contrasted tree shapes in Africa, (2) to identify factors affecting within and between trees wood density, (3) to propose an allometric model that integrates these factors and (4) to evaluate the reliability of using generalized allometric equations in this type of forests. Models were developed to predict wood density and phytomass of the trees based on the harvesting of 42 trees from 16 species, representing three guild status in the wet evergreen forest of Boi Tano in Ghana. Results indicated that the wood density was highly influenced by the tree species, guild status, size of the tree and pith to bark distance. Dry mass of a tree was influenced by diameter at breast height, crown diameter and wood density. The wood density depends on the position of the wood within the tree and the guild status considered. The use of generalized allometric models in literature is limited by the specific climate zone, the consideration of tree height and species specific wood density. In considering those factors, using generalized allometric equations could result in an error of 3%. Further research should better consider the bigger trees and the influence of the topography and ecosystem history.