一种新型竹木集成材粘着剂问世

CU—3型粘着剂为日本株式会社生产,日本竹协会特别推荐的具有超高水平,超高安全性能的水基乙烯聚氨酯型粘着剂。最适合于竹子集成材及各种木质集成材的粘合。作为竹材特选专用粘着剂,CU—3型粘着剂已经在日本国内广泛使用,并博得用户很高的评价。凡使用CU—3型粘着剂的竹木制品能够顺     

森林病虫害经济损失评估的一种新方法——曲线法

森林病虫害通过危害林木的根、干、枝、叶等组织,使林分蓄积量或生物量遭受损失,从而影响森林生态系统服务功能作用的发挥。本文采用林木生长曲线法估算不同林龄林分蓄积量,通过森林生物量转换因子连续函数法（BEF）实现林分蓄积量与生物量的转换。编制了我国主要森林病虫害危害程度分级表、林分蓄积量年生长损失率表和主要林木生物量转换因子基本常数表,并以马尾松为例拟合出林分蓄积量单木生长曲线。确定了我国森林单位重量生物量生态效益值（K）为1476．2元／t。应用林木生长曲线法和生物量转换因子连续函数法评估森林病虫害经济损失适用性强,准确度高,更能反映我国森林病虫害危害程度的实际状况。     

Decay-influencing factors: A basis for service life prediction of wood and wood-based products

The need for a reliable database and a corresponding methodology to predict service life of wood and wood-based products emanates from the European Construction Products Directive, as well as from a strong interest by the building industry. A literature review on decay-influencing factors and on previous approaches to implement methods and tools for service life estimations was the basis for a concept for service life prediction of wooden components. The effect of various indirect decay factors was found to be reducible to a few direct decay factors, with material resistance, as well as wood moisture content, wood temperature and their dynamics among the key factors for fungal decay. Approaches that consider only indirect factors, e.g. climate indices, suffer from poor correlation with service life or decay rates. Therefore, the overall consideration of all possible influences, reduced on the key direct decay factors in first instance, is recommended. To fill a theoretical model with a reliable database, various data sources need to be considered, in decreasing order of priority: in-service performance, field test data, laboratory test data, survey analysis and expert opinion.     

Decay-influencing factors: A basis for service life prediction of wood and wood-based products

Abstract

The need for a reliable database and a corresponding methodology to predict service life of wood and wood-based products emanates from the European Construction Products Directive, as well as from a strong interest by the building industry. A literature review on decay-influencing factors and on previous approaches to implement methods and tools for service life estimations was the basis for a concept for service life prediction of wooden components. The effect of various indirect decay factors was found to be reducible to a few direct decay factors, with material resistance, as well as wood moisture content, wood temperature and their dynamics among the key factors for fungal decay. Approaches that consider only indirect factors, e.g. climate indices, suffer from poor correlation with service life or decay rates. Therefore, the overall consideration of all possible influences, reduced on the key direct decay factors in first instance, is recommended. To fill a theoretical model with a reliable database, various data sources need to be considered, in decreasing order of priority: in-service performance, field test data, laboratory test data, survey analysis and expert opinion.     

A new method for nondestructive evaluation of solid wood moisture content based on dual-energy X-ray absorptiometry

This paper presents a new method to determine the moisture content of solid wood based on the principle of dual-energy X-ray absorptiometry. The study investigates the theoretical relationship between X-ray wavelength and mass attenuation coefficients of wood, water, and reference substance. In accordance with this relationship, a theoretically obtained equation is proposed to calculate the moisture content in wood. The proposed equation is compared to experimental results using small blocks of sugi wood, which showed that the change in mass attenuation coefficient of wood with X-ray tube voltage increased with increasing moisture content as expected from the theoretical equation. A regression equation for moisture content estimation was determined based on the experimental results, and the standard error of estimate in the 0–120 % dry-basis moisture content range using the regression equation was determined to be 21.9 % with the most appropriate pair of tube voltages, 15 and 40 kVp. The accuracy of the method will be improved by reducing the duration of X-ray radiography and by increasing the disparity between paired tube voltages. This method has the potential to determine moisture content of solid wood using X-ray without oven-drying or assuming oven-dry density.     

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.     

紫椴种子层积催芽处理新法

紫椴种子属于综合因素导致的深休眠种子类型,必须进行催芽处理才能解除休眠。传统层积催芽处理发芽率不稳定,通过采取化学和物理方法结合进行层积处理,可使紫椴种子发芽率达到70%以上,苗木生长健壮,超过国家和地方标准规定的技术指标。     

干基腐朽材量材设计新方法的探讨

本文作者根据在张广才岭境内制材厂跟踪调查结果,提出对干基腐朽材的量材设计时,一般树种可按墩根和造短材的习惯量材法的进行划尺,但对可做特级原木或胶合板原木的树种,一定要掌握好腐朽深度,将腐朽部分墩掉,使下节原木变为特级原木或胶合板原木。这种最材新方法对国家和企业都大有好处。     

高等级公路边桩放样的一种新方法

针对高等级公路边桩传统放样方法的不足,提出了一种通过计算路线外任一点至道路中线最短距离放样高等级公路边桩的方法。该方法能大大提高边桩放样的精度与速度。     

A new instrument for measurement and collection of quantitative samples of the litter layer in forests

The litter layer plays an important role in the maintenance of tropical forests. The evaluation of parameters such as thickness or water content can reveal forest conditions that are of global relevance (for example carbon stock) or of local importance such as the conservation of nutrients in native forests or plantations. However, there is no specific instrument or protocol for quantitative collection of the litter layer. We developed an instrument composed of two parts that permits measurement and collection of the litter layer, following a simple protocol. The method was tested in two forest types and we verified the greater accuracy and ease of use of the instrument compared to two other commonly used litter collection methods.     

A NEW METHOD FOR INCREASING THE PRODUCTIVITY OF LARCH PLANTATION

Forestecosystemisanopensystemwithbinarystructure.Ithaskindsofecologicalfunctionsandprovidesallmanykindsofforestproductsandabundantresourceofwoodforhumanbeingsbyexchanginginformationswithenvironment-But,itisknownthattheradiationofsunlightisidenticalinthesameunitareaofthesamelatitude,so,itisadifficultproblemtoincreasetheproductivityofstand.Inthispaper,researchesandanalyseswerecarriedonthetheoryofedgeeffectinordertodevelopthecommunitystructure,Intheend,thecompositionandstructureofphotosyntheticsy…     

THz-imaging: a new method for density mapping of wood

Summary This paper presents a new technique for fast and non-intrusive density mapping of wood based on far-infrared spectroscopy. The transmission of a piece of beech 1.7 mm thick is investigated between 0.1 and 2.5 THz. In this spectral range we find wood to be fairly transparent, but density inhomogeneities and structural details such as annual rings become visible in the transmission profile. The measured absorption correlates well with the wood density independently obtained by the gravitometric-volumetric method. Thus it finally becomes possible to transform the THz images into 2-dimensional density maps.The skillful technical help of Mrs. M. Rinas is greatly appreciated.     

A new on‐site detection method for Bursaphelenchus xylophilus in infected pine trees

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease (PWD), which is a major problem in East Asia and West Europe. Quick identification of PWN is needed to prevent the dispersal of PWD to healthy forests. Various detection methods of PWN have been developed using anatomical characters and molecular markers. These methods are not suitable for rapid diagnosis because it is difficult to distinguish B. xylophilus from the non‐pathogenic species Bursaphelenchus mucronatus based on morphological characters without expertise in nematode taxonomy and most PCR or isothermal amplification detection methods require time‐consuming processes. In this study, we developed an on‐site PWN detection method using a recombinase polymerase amplification (RPA) assay with a novel extraction buffer (DAP buffer). This new PWN detection method is able to extract genomic DNA from PWN in pinewood by simple buffer consisting of sodium hydrate, polyethylene glycol 200 and dimethyl sulfoxide in 10 min without using the experimental devices and able to distinguish between B. xylophilus and other Bursaphelenchus spp. by amplifying the species‐specific 5S rDNA fragment of B. xylophilus in 10 min. Taken together, our protocol can obtain the result for the detection of PWN in pine tree samples within 30 min. This result suggests that RPA/DAP assay is much faster, easier and cheaper than the conventional methods for detecting PWN.     

Mini-cuttings technique: a new ex vitro method for clonal propagation of sweetgum

An efficient production system, which can quickly produce high quality plants, is shown in this study of Liquidambar styraciflua. The mini-cuttings technique was used for ex vitro clonal propagation of three sweetgum clones. The semi-hydroponics system for production of propagules was also tested, and the concentration of indole-3-butyric acid (IBA) for rooting was evaluated. Three adult clones, produced according to conventional cutting processes, were used as mini-stumps and maintained in semi-hydroponics systems of medium size sand. Ten collections of sprouts were prepared to evaluate the production of semi-hydroponics systems (mini-clonal hedges). Sprouts from collection number six were used at different concentrations of IBA solution (0; 500; 1,000; 3,000 and 6,000 mg l⁻¹) to test the mini-cuttings technique. The high survival rates of mini-stumps after ten collections (96.3%), and high annual production per square meter (~2,953 mini-cuttings) showed that the mini-clonal hedges are viable to conduct sweetgum mini-stumps. The formation of 62.5% of healthy plants after hardening under outdoor conditions showed that sweetgum could be successfully propagated by the mini-cuttings technique.     

东莞林科园现代园林花圃规划发展新模式

介绍了东莞林科园(以下简称林科园)现代园林花圃的规划原则及内容，突出了现代花圃生产性及观赏休闲娱乐性的功能特征，以及对苗圃规划中生态学原则的运用。     

A new method for the identification of old-growth trees in National Forest Inventories: application to Pinus halepensis Mill. stands in Spain

Context

Old-growth trees play a very important role in the maintenance of biodiversity in forests. However, no clear definition is yet available to help identify them since tree age is usually not recorded in National Forest Inventories.

Aims

To develop and test a new method to identify old-growth trees using a species-specific threshold for tree diameter in National Forest Inventories.

Methods

Different nonlinear mixed models for diameter–age were generated using data from the Spanish Forest Inventory in order to identify the most appropriate one for Aleppo pine in its South-western distribution area. The asymptote of the optimal model indicates the threshold diameter for defining an old-growth tree. Additionally, five site index curves were examined to analyze the influence of site quality on these models.

Results

The Hossfled III mixed model was found to be the most appropriate to fit diameter–age curves for Aleppo pine trees. The overall diameter at breast height threshold for old-growth trees was 40.6 cm, although over a range of sites with increasing site quality, the threshold figure was 36.0, 38.0, 40.4, 43.1, and 46.3 cm, respectively.

Conclusions

This method allows the identification of old-growth trees and therefore of biodiversity hotspots, thus providing decision makers with a useful tool for management purposes.     

AHP法在木材过坝方式选择中的应用

本文应用层次分析法对机械过坝、船闸过坝、水筏道过坝等几种主要的木材过坝方式进行综合分析,结果表明船闸过坝方式的综合效益最佳,为决策者提供决策依据.     

改善林区无线寻呼信号与调制域特性的一种新方法

本从调制域角度分析了基于ＰＬＬ激励的无线寻呼信号的数字调频特性;发现ＰＬＬ锁定状态下的频率跟踪特性对数字调频有一定影响。阐述了这种影响造成无线寻呼系统误码的机理。最后,本提出了“动态调整ＰＬＬ中心频点”的方法。     

Identification and evaluation of reference genes for normalization in quantitative real-time PCR analysis in the premodel tree Betula luminifera

Betula luminifera is a commercial tree species that is emerging as a new model system for tree genomics research. A draft genomic sequence is expected to be publicly available in the near future, which means that an explosion of gene expression studies awaits. Thus, the work of selecting appropriate reference genes for q PCR normalization in different tissues or under various experimental conditions is extremely valuable. In this study, ten candidate genes were analyzed in B. luminifera subjected to different abiotic stresses and at various flowering stages.The expression stability of these genes was evaluated using three distinct algorithms implemented using ge Norm,Norm Finder and Best Keeper. The best-ranked reference genes varied across different sample sets, though RPL39,MDH and EF1 a were determined as the most stable by the three programs among all tested samples. RPL39 and EF1 a should be appropriate for normalization in N-starved roots,while the combination of RPL39 and MDH should be appropriate for N-starved stems and EF1 a and MDH should be appropriate in N-starved leaves. In PEG-treated(osmotic) roots, MDH was the most suitable, whereas EF1 a was suitable for PEG-treated stems and leaves. TUA was also stably expressed levels in PEG-treated plants. The combination of RPL39 and TUB should be appropriate for heat-stressed leaves and flowering stage. For reference gene validation, the expression levels of SOD and NFYA-3were investigated. This work will be beneficial to future studies on gene expression under different abiotic stress conditions and flowering status in B. luminifera.