长白落叶松提取物对木材防腐作用的研究

以长白落叶松心材、边材及树皮为原料,分别用乙醚、氯仿、丙酮、甲醇和水5种溶剂对其进行提取,采用滤纸片法研究了不同溶剂提取物分别对白腐菌和褐腐菌的抑菌性能,发现心材的甲醇提取物和丙酮提取物对白腐菌有较好的抑制效果,树皮的水提取物对2种菌都有较好的抑制效果.并研究了这两种提取物在室内对木材的防腐性能,借助扫描电子显微镜(SEM)照片观察了木材腐朽后菌丝生长的情况,与常用木材防腐剂酸性铬酸铜(ACC)进行了对比,结果显示:心材的甲醇提取物对白腐菌的抑制效果较好;而树皮的水提取物对褐腐菌抑制效果较好.     

Accoya改性木材

新西兰：试验表明，Accoya改性木材（来自可持续经营林区的针叶材经Accoya技术处理）具有优良的耐久性。Scion，以前的新西兰林业研究所（New Zealand Forest Research Institute）对Accoya改性木材和merbau、cedar、teal（、cypress等几种木材和CCA处理木材进行了历时5年耐久性比较试验，结果表明，Accoya改性木材的状态显著优于其他样品。Accoya改性木材样品只有2个有轻微腐朽，     

怀槐心材提取物的防腐性能及其急性毒性试验研究

以怀槐的心材和树皮为原料,用乙醚、氯仿、丙酮、甲醇和水5种溶剂对其进行浸提,得到10种提取物.这10种提取物对白腐菌和褐腐菌的抑菌性能研究表明,怀槐心材的甲醇和丙酮提取物的抑菌性能良好.将心材的甲醇提取物和无机木材防腐剂酸性铬酸铜(ACC)用于对木材的室内防腐实验,根据腐朽后试样的失重率和扫描电子显微镜(SEM)的照片观测,得出甲醇提取物对白腐菌的防腐作用较好,对褐腐菌的防腐作用很弱,而ACC对两种菌的防腐作用较强.将心材甲醇提取物和ACC用于对斑马鱼的急性毒性试验,测得两者在24、48和 72 h 的半致死浓度,甲醇提取物分别为16.5、12.7、12.0 mg/L,ACC分别为3.2、2.5、2.0 mg/L;两者的安全质量浓度分别为2.26和 0.46 mg/L.     

白桦木材中总酚含量与抗木材腐朽菌的关系

腐朽是木材最严重的生物破坏,它能引起木材结构损坏,造成经济上的巨大损失.白桦(Betula platyphylla)是极易腐朽的树种(李坚,2002).本文利用5种木材腐朽菌对白桦进行生物降解,根据质量损失率筛选出易腐和抗腐植株,进一步研究易腐和抗腐白桦总酚含量的差异与木材腐朽抗性的关系.为今后在林木遗传改良中筛选适宜的天然抗腐朽植株提供理论基础,同时也为森林培育、木材利用等方面的研究提供相关信息,减少防腐剂的使用,降低防腐剂对环境的污染.     

怎样减少贮木场木材的腐朽?

林晓木博士：你好！我们林场贮木场的木材经常发生腐朽，特别是在湿热的气候条件下，为什么？有什么有效的办法来减少木材的腐朽吗？木奇２００１年１１月１０日木奇：您好！您在来信中所说的木材腐朽是由微生物中的真菌作用于木材引起的。木材是一种生物材料，能引起木材腐朽的真菌包括褐腐菌（如密粘褶菌）和白腐菌（如彩绒革盖菌），前者导致木材发生褐腐（褐色腐朽），或叫粉末状腐朽，破坏性腐朽，俗称红糖包型腐朽。其木材典型的症状是外观呈褐色或红色，有如烧焦的木材；质脆，出现垂直于木材纹理的裂纹（龟裂）并伴随着严重的收缩和…     

不同林分密度对桉树幼林木材材性的影响

对两种桉树无性系(巨细桉DH201-2和尾巨桉DH32-29)在5种不同林分密度下(1250、1657、2500、5000和6667株.hm-2)的木材材性(包括木材基本密度和纤维形态特征)进行了测量和研究分析(纤维形态特征分两种不同材型分析:心材与边材)。结果表明:无性系DH201-2的林分密度3(2 500株.hm-2)木材基本密度最大,为452 kg.m-3,DH32-29以林分密度2(1657株.hm-2)的木材密度最大,为436 kg.m-3;相同无性系相同林分密度下,边材纤维长度比心材纤维长度长,边材长宽比一般比心材长宽比要大,纤维宽度则无显著差异;无性系DH201-2的林分密度3(2500株.hm-2)和林分密度5(6667株.hm-2)是符合林分蓄积量、木材基本密度和纤维长度最大值的组合。     

3种季铵盐木材防腐剂的防腐性能和抗流失性比较

以杨木为试材，比较了3种季铵盐木材防腐剂的防腐性能和抗流失性，结果表明，当二癸基二甲基氯化铵（季铵盐-1），二癸基二甲基乙酸铵（季铵盐-2）和二癸基二甲基丙酸铵（季铵盐-3）药剂的保持量分别为3.8,3.8和3.9kg/m^3时，经白腐采绒钳盖菌[Coriolus versicolor(L.exFr.)Quel]腐朽后，试样的质量损失率分别为7.2%,7.9%和7.6%。达到强耐腐等级，另外，二癸基二甲基乙酸铵与木材作用后，对中性和碱惺 溶液性质较为稳定，而二癸基二甲基丙酸铵对酸性溶液较为稳定。     

木材初期腐朽研究综述

木材容易受到各种微生物的侵袭,真菌腐朽是导致木材破坏最严重的一种方式,即使是在木材质量损失率很小的腐朽初期,真菌也可以迅速引起木材结构的破坏,导致木材强度的急剧降低.生物培养和显微镜观察被认为是目前唯一权威的用来检测和评估木材初期腐朽的方法,但这些方法很难对木材的初期腐朽进行快速、准确地评估.因此,寻找一种迅速、准确地检测和评估木材初期腐朽的方法倍受人们的关注.有关初期腐朽及其检测与评估的研究在国外已有大量报道,而在我国却极为少见.本文综述了近几十年国内外有关木材初期腐朽及其检测与评估的研究,旨在增强人们对木材初期腐朽危害的认识,并呼吁有关部门重视相关研究在我国的发展.     

樟树叶提取物对木材腐败菌的抑菌性研究

分别采用水和苯-乙醇提取樟树[Cinnamomum camphora(L.)Presl]叶,用杯碟法测定2种提取物对木材腐朽菌、霉菌及变色菌的抑菌性。结果表明:樟树叶苯-乙醇提取物抑菌测试效果不明显,但樟树水提取物对木材腐朽菌和霉菌具有抑制作用。当测试浓度为5%时,对木材白腐菌黄孢原毛平革菌、褐腐菌密粘褶菌、哈慈木霉菌、产紫青霉菌、烟曲霉菌均有明显抑制,高浓度(10%)时能抑制蓝变菌可可球二孢菌。     

壳聚糖在木材防腐中的应用

壳聚糖是在虾、蟹等甲壳类动物中提取的一种天然高分子多糖，具有来源广泛、绿色低毒等优点，是一种颇有潜在应用价值的环保型木材防腐剂。本文从壳聚糖对木材防腐剂的固着、对木腐菌的抑制、及其在木材防腐上的应用这三个方面进行阐述，归纳总结了单一壳聚糖、复合壳聚糖以及纳米壳聚糖对木材腐朽菌的抑制作用，展望了壳聚糖在木材防腐的发展趋势，以期推动壳聚糖在木材防腐领域中的应用和发展。     

Volatile composition analysis by solid-phase microextraction applied to oak wood used in cooperage (Quercus pyrenaica and Quercus petraea): effect of botanical species and toasting process

The purpose of this study was to investigate the sorption of selected volatile substances from oak wood-chip samples (Quercus pyrenaica Willd. and Quercus petraea L.) subjected to different toasting levels, namely, without toasting, with medium toasting, and with strong toasting, through the use of solid-phase microextraction (SPME). The main volatile compounds identified as a function of the toasting level and botanical species were furfural, hexanal, α-pinene, d-limonene, decanal, vitispirane, ethyl hexanoate, cis-3-methyl-γ-octalactone (“oak lactone” or “whisky lactone”), α-terpineol, p-xylene, and nonanal. Considering the data obtained from the toasted woods (medium and strong intensity) in comparison with those of nontoasted woods, it can be pointed out that the average peak area and the number of compounds identified in the gas chromatogram decreased during the toasting process. In general, regarding the compounds analyzed, quantitative differences were found between the two oak wood species under study. High values of volatile compounds were found in Quercus pyrenaica oak wood chips. In addition, for the number of compounds identified in oak wood extracts and directly extracted from solid oak wood chips by SPME, it is concluded that the best extraction process for volatile compounds from oak wood is the use of oak wood-chip liquid extracts.     

Acetaldehyde emission from wood induced by the addition of ethanol

A mechanism of acetaldehyde emission from wood induced by the addition of ethanol was proposed. It is known that acetaldehyde generation is due to the oxidation of ethanol via a metabolic process involving alcohol dehydrogenase (ADH) in living bodies. However, it remains unclear whether the enzymatic alcohol oxidation is applicable to wood. We investigated possible factors of wood parts, conditioning, storage sites, and heating and sterilization treatments on acetaldehyde emission using the syringe method and HPLC analysis. We reconfirmed that acetaldehyde emission was observed only when ethanol was added to wood. Greater acetaldehyde emissions were obtained in heartwood compared to sapwood in both Japanese cedar (Cryptomeria japonica D. Don) and Japanese cypress (Chamaecyparis obtusa Endl.) specimens. In addition, an acetaldehyde conversion rate of 1–2 mol% was determined in green cedar heartwood samples, while, conversely, air-dried cedar heartwood samples showed 4–5 mol%. Ethylene oxide gas sterilization had the effect of decreasing acetaldehyde emission on air-dried wood, but not on green wood. Autoclave sterilization could completely prevent acetaldehyde emissions from both green and air-dried wood. These results suggested that an original ADH in wood and an attached ADH from the outside via microorganisms onto wood were assumed to be the primary causes of acetaldehyde emissions from wood induced by the addition of ethanol.     

Influence of Ammoniacal Copper Quaternary treatments on mechanical properties of blue-stained Lodgepole Pine wood

Three concentrations （2.8%, 2.0%, 1.2%） of Ammoniacal Copper Quaternary （ACQ） was selected to treat Lodgepole pine wood for evaluating ACQ treatment on mechanical properties of blue-stained wood. The bending modules of elasticity （MOE）, modules of rupture （MOR）, toughness and shearing strength parallel to grain on tangential surface, are tested according to the criteria GB1927-1943-91. Non-treated sample were also tested according to the same procedure. The results showed that the three groups specimen impregnated by different concentrations of ACQ solution met the AWPA standard 2003 of America （UC4A 6.4g/cm^3）. There were significant difference of toughness between treated wood and non-treated wood （p=0.01）, but there were no statistically significant differences among three concentrations in terms of toughness, and toughness of treated wood was approximately 20% lower than non-treated. MOR, MOE as well as sheafing strength parallel to grain were found to be not significantly different between treated wood and non-treated one, and there were no statistically significant difference among three concentrations of ACQ too. Toughness, MOR, MOE and sheafing strength parallel to grain increased with decrease of concentration of ACQ, but they were hardly affected by ACQ preservatives.     

Dose–response relationships between wood moisture content,wood temperature and fungal decay determined for 23 European field test sites

Scots pine sapwood (Pinus sylvestris L.) and Douglas fir heartwood (Pseudotsuga menziesii Franco) specimens were exposed in double layer field trials at 23 different European test sites under different exposure conditions (in total 27 test sets). The material climate in terms of wood moisture content (MC) and wood temperature was automatically monitored over a period of up to 7 years and compared with the progress of decay. The overall aim of this study was to establish dose–response relationships between climate factors and decay as a basis for the service life prediction of wood. The “Scheffer Climate Index” based on weather data collected at official meteorological stations at the different test sites poorly correlated with the corresponding decay progress and was therefore not a suitable tool for estimating site-specific decay potential. In contrast, the use of the combined material climatic parameters MC and wood temperature led to a feasible dose–response function and turned out to be a useful basis for service life prediction of wood.     

Anisotropy of wood vibrational properties: dependence on grain angle and review of literature data

The anisotropy of vibrational properties influences the acoustic behaviour of wooden pieces and their dependence on grain angle (GA). As most pieces of wood include some GA, either for technological reasons or due to grain deviations inside trunks, predicting its repercussions would be useful. This paper aims at evaluating the variability in the anisotropy of wood vibrational properties and analysing resulting trends as a function of orientation. GA dependence is described by a model based on transformation formulas applied to complex compliances, and literature data on anisotropic vibrational properties are reviewed. Ranges of variability, as well as representative sets of viscoelastic anisotropic parameters, are defined for mean hardwoods and softwoods and for contrasted wood types. GA-dependence calculations are in close agreement with published experimental results and allow comparing the sensitivity of different woods to GA. Calculated trends in damping coefficient (tanδ) and in specific modulus of elasticity (E′/ρ) allow reconstructing the general tanδ-E′/ρ statistical relationships previously reported. Trends for woods with different mechanical parameters merge into a single curve if anisotropic ratios (both elastic and of damping) are correlated between them, and with axial properties, as is indicated by the collected data. On the other hand, varying damping coefficient independently results in parallel curves, which coincide with observations on chemically modified woods, either “artificially”, or by natural extractives.     

A Service Test of Treated Louvres in a Cooling Tower

The performance of wooden louvres treated with four preservatives (Celcure A, copper sulfate + sodium pentachlorophenate, pentachlorophenol and Tanalith C) and exposed in a cooling tower in Pretoria is described. The copper-chrome-arsenate (CCA) preservatives Tanalith C and Celcure A (at retention of 30 kg/m³) protected the louvres very well against deterioration. Untreated Pinus canariensis wood outperformed P. pinaster and P. radiata wood.     

Comparative study on three dynamic modulus of elasticity and static modulus of elasticity for Lodgepole pine lumber

The dynamic and static modulus of elasticity （MOE） between bluestained and non-bluestained lumber of Lodgepole pine were tested and analyzed by using three methods of Non-destructive testing （NDT）, Portable Ultrasonic Non-destructive Digital Indicating Testing （Pundit）, Metriguard and Fast Fourier Transform （FFT） and the normal bending method. Results showed that the dynamic and static MOE of bluestained wood were higher than those of non-bluestained wood. The significant differences in dynamic MOE and static MOE were found between bulestained and non-bluestained wood, of which, the difference in each of three dynamic MOE （Ep. the ultrasonic wave modulus of elasticity, Ems, the stress wave modulus of elasticity and El, the longitudinal wave modulus of elasticity） between bulestained and non-bluestained wood arrived at the 0.01 significance level, whereas that in the static MOE at the 0.05 significance level. The differences in MOE between bulestained and non-bluestained wood were induced by the variation between sapwood and heartwood and the different densities of bulestained and non-bluestained wood. The correlation between dynamic MOE and static MOE was statistically significant at the 0.01 significance level. Although the dynamic MOE values of Ep, Em, Er were significantly different, there exists a close relationship between them （arriving at the 0.01 correlation level）. Comparative analysis among the three techniques indicated that the accurateness of FFT was higher than that of Pundit and Metriguard. Effect of tree knots on MOE was also investigated. Result showed that the dynamic and static MOE gradually decreased with the increase of knot number, indicating that knot number had significant effect on MOE value.     

Spectrochemical characterization by FT-Raman spectroscopy of wood heat-treated at low temperatures: Japanese larch and beech

Test samples of Japanese larch (Larix leptolepis) heartwood and Japanese beech (Fagus crenata) sapwood were heated for 22 h at constant temperatures (50°–180°C) under three water content conditions. Raman spectra of the samples were recorded before and after the heat treatments, and spectral changes in the range from 1000 cm⁻¹ to 1800 cm⁻¹ were evaluated using the difference spectrum method. For both wood species, the Raman band intensity at 1655–1660 cm⁻¹ due mainly to the C=C and C=O groups in lignin clearly decreased with increasing heat-treatment temperature (HTT). The spectral change was thought to reflect the progress of condensation reactions of lignin molecules during the heat treatment. Moreover, the decrease in band intensity was considerably facilitated by the presence of water in the cell wall, suggesting that the condensation is closely related to the softening of lignin. From the spectral changes in the wavenumber region of 1200–1500 cm⁻¹, it was considered that wood constituents are partially decomposed at the higher HTT. Part of this article was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, March 2003     

Distribution of boron in wood treated with aqueous and methanolic boric acid solutions

The distributions of boron in Japanese cedar (Cryptomeria japonica D. Don) sapwood blocks treated with aqueous or methanolic boric acid [B(OH)₃] solutions were explored through Raman spectroscopy and prompt gamma-ray analysis (PGA). B(OH)₃ was the sole boron species observed in Raman spectra of the wood blocks treated with either solution. Plots of weight gain of the treated wood blocks versus boron concentration in treatment solutions were found to be linear. The results indicated that the methanolic solution makes it possible to impregnate wood with much larger amounts of boron than the aqueous solution. PGA confirmed that B(OH)₃ was highly enriched near the end grains of the treated wood blocks. Raman measurements suggested that boron content in the bulk of the wood block is not as large as expected from the weight gain of the treated wood blocks when an ordinary air-drying method is used. It was concluded that the aqueous solution impregnates the cell walls of wood with boron more easily than the methanolic solution. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society. This article follows the previous rapid communication “Analysis of boron in wood treated with boric acid solutions using Doppler broadening method of prompt gamma-rays.” J Wood Sci (2006) 52:279–281     

Effect of different drying methods on liquid penetration of Chinese fir plantation wood

Chinese fir plantation sapwood and heartwood boards were treated by three drying methods: radio frequency-vacuum drying (RFVD), conventional kiln drying (KD) and high temperature drying (HTD). The maximum amount of dyeing solution uptake by the capillary rising method was used to evaluate the liquid penetration of the treated wood. The pit aspiration ratio was determined by a semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results show that liquid penetration of Chinese fir sapwood after RFVD is significantly higher than that after KD and HTD. Liquid penetration of Chinese fir heartwood after RFVD is higher than that after HTD. Liquid penetration of Chinese fir sapwood is significantly higher than that of heartwood after three drying treatments. Low pit aspiration ratio and cracks of some bordered pits are the main reasons for the increase in liquid penetration after RFVD treatment. __________ Translated from Scientia Silvae Sinicae, 2006, 42(10): 85–90 [译自: 林业科学]