桉树材性性状近红外预测模型的建立

试验以采集的100份桉树不同组合杂交子代的木芯及木粉样品作为研究对象,以常规方法测定所取木材样品的木材密度、纤维长度和纤维宽度并用 Polychromix 手持式近红外仪采集了自然风干状态木粉的近红外光谱信息。光谱数据的处理及建模用 Unscrambler 9.7软件完成。建模结果显示：木材密度、纤维长度和纤维宽度的预测精度均可达90%以上。建模过程中,木材密度较纤维长度和纤维宽度所需的校正样本集数量要多,说明要达到一定的预测精度,纤维长度和纤维宽度其所建模型的预测范围会相应变小。     

Genetic variation and relationships to growth traits for microfibril angle,wood density and modulus of elasticity in a Picea abies clonal trial in southern Sweden

Abstract

Genetic variation in wood density, microfibril angle (MFA), wood stiffness (MOE), height, diameter and volume was investigated in a 26-year-old Norway spruce [(Picea abies (L.) Karst.] clonal trial in southern Sweden. Wood quality measurements were performed on 10 mm increment cores using SilviScan. For MFA, mean values of annual rings showed the highest value (30°) at ring 2 counting from the pith, followed by a steep decrease and a gradual stabilization around ring 12 at approximately 14°. MOE showed a monotonic increase from 5 GPa to 14 GPa when moving from pith to bark. High broad-sense heritability values were found for wood density (0.48), MFA (0.41) and MOE (0.50). All growth traits displayed heritability values of similar magnitudes as reported in earlier studies. The generally high age–age correlations between different sections of the wood cores suggested that early selection for wood quality traits would be successful. Owing to unfavorable genetic correlations between volume and MOE, the correlated response indicated that selection for volume only at age 10 would result in a 0.27% decrease in weighted MOE at age 26 for every 1% increase in volume.     

Age trends and correlations of growth and wood properties in clone of Eucalyptus urophylla × E. grandis in Guangdong, China

We assessed growth traits and wood properties of DH 32-29, a clone of Eucalyptus urophylla × E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were significant differences (1% level) on all studied traits among ages except for wood basic density. Analysis of age trends of growth traits and wood properties revealed that rotation length of DH32-29 should be more than six years or longer. Phenotypic correlations among traits at individual ages indicated that correlations between growth traits were strongly positive. There was significant change in relationship between growth and wood basic density with increasing age, ranging from -0.03 to -0.54 at 2 and 5 year and 0.003 to 0.3 at 3, 4 and 6 year.Correlations between Pilodyn pin penetration and basic density measuredon increment cores showed that Pilodyn could rank or group genotypesor sites into density classes, but failure to predict individual tree and individual clone.     

杨树幼株、苗杆生长及材性差异研究

通过对杨树中汉107号无系性幼林采样测定发现,2～8a生幼树胸径处去皮后木材基本密度、纤维含量、纤维长度都随树龄增加而略增大,分别于第6年、第6年、第5年时基本上稳定下来,达到工艺成熟;幼树木材连年生长量总体趋势是随着年龄的增加而增大,第7年时达到极高值,第8年开始下降。综合杨树不同树龄时生长与木材材性情况,杨树的主伐期定为8a是比较理想的。另外通过对杨树1～5a蔸1a生苗杆的各项指标测定表明:采用“割韭菜”式的经营杨树直接用于制浆、人造板,工艺上是不成熟的。     

Potential Measures for Use in Developing Selection Procedures for High Timber Density in Juvenile Wood of Picea sitchensis

Four clones of Picea sitchensis, each growing on two sites with contrasting growth rates, were examined for the rate at which wood density decreased as growth rate increased during successive years of juvenile wood formation. The clones with the greatest and least rates of change were consistent between contrasting sites. It was determined that the most effective measure of change in wood density was the relative rates of increase in wood volume and wood weight increment in successive annual increments. Wood volume increased more rapidly than wood weight for all clones but there were differences between them. The rankings for these relative rates of change were not (he same as those for mean density nor density of the last annual wood increment. Within a single annually produced sheath of wood, wood density was found to decrease with increasing distance down the main stem. In the outermost sheath, volume increment was at a maximum at least two and more usually three interwhorl positions. Dierences between clones in the patterns of weight and volume increment along the main stem are related to differences in crown structure. It is suggested that small height increments along the main stem lead to inadequate surface area for cambial development relative to the available resources for growth.     

Moisture content measurements in wood using dual-energy CT scanning – a feasibility study

Currently computed tomography (CT) scanning provides a non-destructive method to determine moisture content in wood in three dimensions. With the current methodology two measurements are needed, one with the scanned piece of wood’s moist state and one after drying. Then the difference of the images can be calculated. The drawback and challenge is that dimensional changes due to shrinkage of wood in the drying process have to be compensated for by image processing. In this study a dual-energy CT scanning method is tested based on the consecutive scanning of wood samples at different energy levels to differentiate water from wood, without the necessity to dry the sample and thus without the need for complex image correction. Not quantified but visible differentiations due to moisture content were obtained on small cubical pine samples of different densities by quick consecutives scans at 60 and 200?kV. The results suggest that given that the pixels in the CT images are representing absorption coefficients it should be possible to directly measure moisture content in wood non-destructively in small volume elements inside solid wood in three dimensions. Further applications of this technique in industrial CT scanning of wood are discussed.     

The laser-sandblasting method: A new method for the qualitative annual ring analysis of conifers

Summary For the assessment of many different aspects of growth processes in trees millions of annual rings are being measured all over the world every year. Other studies dealing with the prediction or explanation of wood properties also require numerous density measurements. While the density of a wood sample is relatively easy to determine by stereogravimetric methods, density relationships or variations within a piece of wood and within individual annual rings can only be detected by time-consuming techniques, e.g. radiodensitometry. A new, simplified method for ring analysis was developed with the aid of the sandblasting and laser sensor method. This process permits the automatic recording of annual radial increment and simultaneously provides results on the mean and intra-annual density of the wood specimens. Sandblasting of cross-sections of stems or of radial strips produces hardness profiles. Due to the hardness variations in these profiles individual annual rings can be more or less easily identified macroscopically, depending on the wood species. Furthermore, density variations are also macroscopically visible on account of the relationship between abrasion depth and density: Sandblasting can be said to provide a three-dimensional representation of the density relationships in wood. Following the numerical recording of these surface profiles with the aid of a laser sensor and upon conversion of abrasion depth profiles into density profiles radial increment and density parameters for stem radii, segments of radii or even individual annual rings can be determined. A comparison with the conventional radiodensitometric ring analysis method shows very good correlations with the results achieved in this study. The advantage of the laser-sandblasting method is that large samples can be investigated without great preparatory effort and in a single processing step.     

几个黑杨杂交无性系的材质测定及其评价

杨树是我国重要的速生树种,也是作为造纸等工业原料的重要树种。生长量是杨树的重要性状指标,但除此之外,容积密度和纤维长等在材性上表现较佳的优良品种的培育也越来越受到社会的关注。中国的杨树材质研究过去大多都只一味地注重和研究与材性有关的性状,此次我们利用多个性状求出了选择指数,然后初步选择了生长量较好,且容积密度等材性性状也表现良好的无性系。调查对象为湖北省石首市原种场内栽植的13a生中天1号、中天4号、中潜1号、中监1号等13个无性系。调查项目为胸径及容积密度、纤维长、弹性模量等材性性状.参试株数为每个无性系16株(1个小区4株,重复4次)共208株。采用“日本林木育种中心”开发的方差分析软件Lsab02和Lsab21求出了最小二乘推定值,对无性系进行了评估,并利用胸径、容积密度、纤维长等性状求出了选择指数,初步选择出了生长和材质上均表现较佳的优良无性系。     

红豆树等6种珍贵用材树种的生长特性和材性分析

利用浙江龙泉和庆元两地在较好立地上营造的21 36年生红豆树、江南油杉、伯乐树、闽楠、刨花楠和乐东拟单性木兰6种珍贵用材树种的片林,以研究其生长、干形和木材基本密度的变化规律。研究结果表明,红豆树是一个树高和胸径生长量大、径生长速生持续期长、木材基本密度中等及其径向均匀性较高的珍贵用材树种,平均年轮宽度达到0.8 1.2 cm,36年生时按宽度和面积计算心材比例分别为60.57%和37.47%。因红豆树分叉干特性明显,在栽植的第2年就应及时修枝抹芽和施肥,以培育树干通直、心材比例高的优质干材。江南油杉和闽楠等其它5种珍贵用材树种皆较少分叉干,其树干通直。闽楠以材质优良而闻名,木材密度中等,虽然其生长速度较慢,但生长势很强,年生长量稳定,加之树冠窄小,适宜长周期大径材的培育;伯乐树生长速度中等,木材密度略低,但其径向均匀性较高,宜作为优质的工艺材来培育;树冠窄小的乐东拟单性木兰生长速度中等,但其木材密度大、径向均匀性高,是优良的珍贵用材树种;江南油杉是个早期生长快而后期生长慢,木材密度中等的针叶树种,可通过加强经营管理延长速生期和提高木材密度的径向均匀性;刨花楠虽然生长速度中等,但其木材密度却较低,浸水有粘液,不宜作为珍贵用材树种培育。     

Can wood density be efficiently selected at early stage in maritime pine (Pinus pinaster Ait.)?

Growth and stem straightness are the two main selection criteria in the French maritime pine breeding programme. In this contribution, our objective was to study the possibility of selecting for wood density assessed at an early stage. We measured X-ray wood density, in three progeny tests, on more than 1 900 breast high increment cores. High relative expected genetic gain (from 3 to 9%) was found for wood density at mature stage. Juvenile and adult wood density estimations were well-correlated; the relative efficiency of early selection reached about 80% at 12 years old. As it would not be realistic to use the X-ray densitometer at an operational scale in a breeding programme, we tested the efficiency of using the Resistograph, an indirect method to assess wood density on live trees. High correlation between the Resistograph and density data (R ² = 0.93 on familial data) was found, suggesting that wood density through Resistograph assessment could be soon integrated as a new selection criterion in our breeding programme.     

基于计算机断层扫描技术的木材密度检测研究

使用计算机断层扫描技术进行原木无损检测,通过对原木树种断层 CT 值的统计,对 CT 设备在检测过程中的窗宽与窗位进行了设定,同时拟合出了木材 CT 值一密度值的线性方程,为原木缺陷的无损检测及木材密度的测定提供一种新方法。     

Determination of specific gravity of green Pinus taeda samples by near infrared spectroscopy: comparison of pre-processing methods using multivariate figures of merit

Near infrared diffuse reflectance was used for the determination of specific gravity in green Pinus taeda L. wood samples representing simulated increment cores obtained at breast height and merchantable green logs. The effects of using three pre-processing methods (second derivative, multiplicative scatter correction, and orthogonal signal correction) to reduce the scatter observed in the original spectra were evaluated. The effectiveness of each method was assessed in terms of the average predictive ability of the models and in terms of multivariate figures of merit derived from net analyte signal theory. Specific gravity was successfully modeled using green wood samples. No differences in predictive ability among models were found, although more parsimonious regressions were obtained using transformed spectra. The incorporation of figures of merit for the characterization of calibration models proved to be a valuable tool for understanding the effects of the pre-processing alternatives on the final results.     

Smart increment borer: a portable device for automated sampling of tree-ring cores

Manual sampling of large number of cores is an arduous task, especially when core diameter is large. We developed an automated tree-ring sampling device, the “smart increment borer”, to increase the sample throughput and minimize the need for muscular exertion. The lightweight, portable device employs a battery-powered electric wrench and the complete system to drive the boring operation weighs less than 10 kg. It is capable of taking both 5- and 12-mm diameter cores of more than 80-cm length. Compared to equipment used in previously published articles, this device enables more rapid sampling and demonstrates a superior torque output/total weight ratio. The device is also capable of facilitating the starting operation of a 12-mm increment borer. It facilitates a variety of effective sampling solutions for dendrochronology/climatology and wood anatomy/quality research.     

不同产地刺猬紫檀木射线组织比较解剖研究

以产自非洲国家的刺猬紫檀 (Pterocarpus erinaceus ) 木材为样品,测定分析木射线宽度与高度 的尺寸、细胞数目,木射线比率。结果表明：轴向薄壁组织带中的射线宽度尺寸均大于木纤维带中的射 线宽度尺寸。木射线的细胞数目及木射线比率则差异性小。从木射线组织解剖结果看,采自西非7 个国 家的刺猬紫檀应该同属一个木种。     

林木剩余物与聚苯乙烯泡沫复合材料研究

研究利用林木剩余物碎料和发泡聚苯乙烯并添加胶粘剂、助剂等进行加压制造复合材料.以导热系数、压缩强度、尺寸稳定性作为主要技术指标对复合材料进行评价,考察了木质碎料与聚苯乙烯泡沫不同配比、施胶量、密度等工艺参数对复合材料性能的影响,并利用扫描电镜对复合材料的界面进行了分析.结果表明:在设定密度范围内,由于胶粘剂、助剂和压力的共同作用,使木质碎料与发泡聚苯乙烯间形成蓬松状结合;正交试验确定的最佳工艺为:发泡聚苯乙烯与木材碎料配比为12∶88、施胶量12%、助剂2%、密度0.20g/cm3.用该工艺制造的复合材料达到相关标准要求.     

近红外光谱技术及其在木材科学中的应用

近红外光谱技术是一项新的木材无损评价方法,能够迅速、准确地对生长锥、固体木材或木粉等试样的性质进行全面无损评价,目前已广泛应用于木材性质预测、木材加工利用等方面的研究中,并为林木的定向培育、木材的遗传改良和高效利用提供技术支持。本文介绍了近红外光谱技术的基本原理及其主要应用,重点介绍了木材的近红外光谱技术及其在木材化学组成、物理力学性质、木材加工利用和木质复合材料等方面的研究成果及应用。     

Cellulose content as a selection trait in breeding for kraft pulp yield in Eucalyptus urophylla

? The aim of this study was to investigate the effectiveness of using cellulose content, measured by the diglyme-HCl method, as a selection trait in breeding programs for kraft pulp yield in Eucalyptus urophylla.

? A total of 275 trees from sixty-two families were sampled from a thinned progeny trial of E. urophylla in northern Vietnam to evaluate cellulose content from breast-height increment cores. Among those, twenty unrelated trees were felled to evaluate cellulose content and pulp yield from breast-height disk samples.

? The regression of pulp yield of disk samples on cellulose content was strong either from disks (R ² = 0.83) or increment cores (R ² = 0.69). There was no significant difference in cellulose content between the provenances. The narrow-sense within-provenance heritability of cellulose content was 0.50 and the coefficient of additive genetic variation was 3.9%. Genetic correlations between cellulose content and growth (0.28–0.45) or wood basic density (?0.02) were not significantly different from zero.

? Breast-height increment core cellulose content measured by diglyme-HCl method is under strong genetic control and can be used to rank trees for pulp yield in E. urophylla plantations. Selection for increased cellulose content would have only minor effects on growth and wood basic density.

     

Batch measurements of wood density on intact or prepared drill cores using x-ray microdensitometry

The performance of a batch scanning x-ray densitometer for measuring wood density without sample preparation, i.e., on intact drill cores, or on rectangular samples prepared from drill cores, was analysed. Effects of x-ray intensity, sample thickness and fiber direction, as well as extractives content, were evaluated for young (mainly sapwood) and old (mainly heartwood) wood from Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). The x-ray power level used as standard (1.4 kW; 40 kV and 35 mA) seemed appropriate for the tested species and specimen thickness. The density of intact drill cores could be determined with a mean standard deviation of 1.6% for each sample, with a single machine run, if the cores were mounted with a fixed fiber direction and calibrations were made for each wood type. The corresponding precision for rectangular samples was 1.0%. Further improvements are attainable by using standard reference samples in each machine run and batch-wise analysis. For the chosen wood types and measurement technique, a sample thickness of 5 mm should give the best precision. However, for species with very narrow rings, thinner samples would improve the spatial resolution when ring boundaries are angled or curved. Extractives should be removed, especially for pine, but possibly also for spruce, if high precision in density determination is required. Received 19 January 2000     

山杨材性群体变异趋势及个体遗传差异的研究*

在山杨主要分布区随机抽取６个天然群体，每群体随机抽样１５株采集木芯，分析结果表明：群体间及个体间的木材密度和纤维长度差异都极显著。群体平均密度０．４３２ｌｇ／ｃｍ３，极差０．０６６２ｇ／ｃｍ３；平均纤维长度１．０７７５ｍｍ，极差０．２６５０ｍｍ。东北、华北群体的密度呈梯度变异，纤维长度的梯度变异不明显。木材密度群体重复率０．５４１，个体重复率０．４７１；纤维长度重复率分别是０．４７１与０．４１２。不同群体、不同年轮组的密度与纤维长度的个体重复率有所不同。密度、纤维长度等与生长性状呈微弱遗传相关，可以进行材性与生长的同步遗传改良。     

栽培措施对短周期工业材材性影响规律的研究

对4种不同栽培措施的日本落叶松、湿地松、马尾松和杉木等多种短周期工业材309株样木的材性进行了全面测试分析研究，结果表明．立地指数大，木材生长率和纤维宽度大．但纤维长度、纤维长宽比、木材基本密度、顺纹抗压强度和抗弯弹性模量减小；立地指数相差两级，木材的年龄宽度、纤维宽度、长度和微纤线角度的差异达到显著或极显著水平栽植密度小，木材的年轮宽度和干缩比增大但纤维长宽比及体积全干缩率减小；栽植密度增大，杉木和昭林6号杨木材的力学强度提高，但尾叶桉和I－69杨降低；不同栽植密度的木材pH值及酸碱总缓冲容量，都是心材大于边材，但木材的脲醛树脂胶凝速度，则是边材快于心材.与未间伐林分的木材比较，随着间伐强度的增大、年轮宽度增大．但纤维长宽比和微纤丝角度减小；间伐强度增大，针叶树村的力学强度降低，阔叶树树则提高．但将强度间伐材（间代40％）与未间伐材比较，结果完全相反；北京杨木材心材的pH值、酸碱缓冲容量及总容量，均随间伐强度的增大而增大，但边材却减小．施肥措施能够增大纤维直径，但将导致纤维长宽比、木材密度和力学强度的降低施肥可以使树木速生，但会降低木材密度和质量，在培育建筑结构材的林分应慎用．