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HOU Zhuqiang GUAN Ning ZHANG Lifei ZHANG ShouhuaiResearch Institute of Wood Industry. Chinese Academy of Forestry Beiiine . P.R. China 《中国林业科技(英文版)》2003,(2)
Woods from Korean Larch, Chinese Fir, Aspens, Manchumian, and Fortunes Paulownia were chosen for investigation. Specimens cut from the air-dried woods had a cubic shape with nominal air-dried size of 17.0 mm and 8.5 mm. Oven-died specimens were put in containers filled with water and water sorption was implemented at atmospheric pressure and room temperature. Results from the experiment could not described exactly by the model of steady state flow from Darcy' law. An empirical equation is put forward for the relationship between the water uptake and immersion time. Meanwhile the immersion time for the maximum water uptake (MWU) was predicted from the water sorption rate. The water sorption behaviors above the fiber saturation point (FSP) differed among five tested woods. Size of specimens had an influence on the water sorption. Small specimens reached their MWU more quickly than large specimens, while large specimens have a higher water sorption rate than those of small ones. MWU was estimated, and the 相似文献
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树皮板的研究及开发可行性 总被引：1，自引：0，他引：1
简要介绍了国内外树皮板的研究和开发情况,并以落叶松树种为例,从其资源状况、组成成分、树皮板的加工工艺等方面,对开发落叶松树皮板可行性进行探讨,旨在提出利用落叶松树皮加工制造实用产品的新思路。 相似文献
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Dong-heub Lee Myung Jae Lee Dong-Won Son Byung-Dae Park 《Wood Science and Technology》2006,40(3):228-236
The extended use of woods treated with traditional or alternative preservatives for exterior applications requires an assessment
of wood adhesive performance. This study attempts to evaluate the performance of wood adhesives for woods treated with various
waterborne preservatives. Two softwood species, i.e. Korean pine (Pinus koraiensis Sieb. et Zucc.) and Japanese Larch (Larix leptolepis [Sieb. et Zucc.] Gordon) were treated with copper–chrome–arsenic (CCA), CB-HDO, or copper azole (CY), and then bonded with
four different wood adhesives such as urea–melamine–formaldehyde (UMF) resin, melamine–formaldehyde (MF) resin, phenol–formaldehyde
(PF) resin, and resorcinol–formaldehyde (RF) resin. The performance of these adhesives was evaluated by measuring the dry
shear strength of adhesive-bonded wood block on compression. Both UMF and MF resins produced a relatively strong adhesive
strength for CY-treated pine and larch woods. The PF resin also produced good bond strength when bonded with either larch
wood treated with CY or pinewood treated with CB-HDO. The best result was obtained when the CB-HDO-treated woods were bonded
with RF resin. For a better bond strength development, a proper combination of adhesive, preservative, and wood species should
be selected by taking into consideration of the characteristics of these three parameters as well as their interactions. 相似文献
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采用多元非线性回归方法分析速生阔叶木材的制浆得率与其化学组分、纸浆的抗张指数、撕裂指数分别与纤维形态的相关性,建立速生材制浆性能的预测模型,选取代表性的速生木材进行材性分析和制浆性能试验研究,用实测值与预测模型算出预测值进行对比.结果证明:预测值与实际测定值拟合得很好,预测模型的精度高. 相似文献
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华北落叶松和同龄的长白落叶松相比照,无论是平均胸径、平均树高还是平均材积,前者都落后于后者,现已形成低质低效林分,没有实用价值。因此,应尽快伐除华北落叶松,按照适地适树的原则,采取人工更新恢复森林。 相似文献
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大兴安岭兴安落叶松原始林倒木养分含量研究 总被引：2，自引：1，他引：1
在大兴安岭兴安落叶松原始林内选择杜香-兴安落叶松林、草类-兴安落叶松林和杜鹃-兴安落叶松林3个典型林型,按照不同树种对倒木的养分含量进行了测定。依据现有的资料,结合研究对象实际,制定了大兴安岭兴安落叶松原始林落叶松和白桦倒木的腐朽等级划分标准。结果表明:不同林型内不同树种倒木有机C、全K、全Na,以及Ca和Mg的含量随着倒木的不断分解均没有明显的变化规律;全N含量均有增加的趋势;全P均保持相对稳定。对3个林型内兴安落叶松倒木的各养分含量之间进行对比,有机C、全K、全P百分含量均为杜鹃-兴安落叶松林﹥草类-兴安落叶松林﹥杜香-兴安落叶松林;全N、全Na和Ca百分含量均为杜鹃-兴安落叶松林﹥杜香-兴安落叶松林﹥草类-兴安落叶松林;Mg百分含量为草类-兴安落叶松林﹥杜鹃-兴安落叶松﹥杜香-兴安落叶松。 相似文献
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H. Matsuda 《Wood Science and Technology》1987,21(1):75-88
Summary Preparation and utilization of esterified woods bearing carboxyl groups are reviewed. The esterified woods are prepared by the addition reactions of wood with dicarboxylic acid anhydrides in the presence or absence of a solvent such as dimethylformamide. The reactions without solvent are industrially advantageous and can give esterified woods with a wide range of monoester contents. The esterified woods can be molded into sheets by hot pressing. By addition reactions of the esterified woods with epoxide, or epoxide and anhydride at high temperatures, epoxide-adducted esterified woods and oligoesterified woods are obtained. These can also be molded by hot pressing. The addition of epoxide to esterified woods results in an improvement in moisture resistance of the molded sheets. When esterified woods are subjected to crosslinking reactions with bisepoxide both at high temperatures and under high pressures, the wood components plasticize to give reddish brown, yellowish brown, or blackish brown crosslinked wood boards whose surfaces are smooth, glossy, and plastic-like. Among the plastic-like crosslinked wood boards, the phthalic anhydride-based board shows the best physical properties. Especially, this board exhibits very high compressive strength and water resistance. 相似文献
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Glen Affric, a National Nature Reserve of international conservationimportance for plant and animal communities associated withScots pine (Pinus sylvestris) woodland is managed for natureconservation and woodland restoration at a landscape scale.Management plans have drawn on information on current standstructure and variation but have not used in any detailed waythe analyses of past tree population changes from sources, suchas pollen analyses. This paper reports the results of pollenanalyses from three small peat hollows at the head of Loch Beinna' Mheadhoin. The analyses demonstrate, first, that woods inthe east of the reserve several centuries ago were differentin species composition and were more varied than they are todayand, second, that the currently patchy Pinus wood in the westof the reserve, at the head of Loch Beinn a' Mheadhoin, is theresult of recent spread westward onto former heathland. Thistemporal and spatial variability in the recent past has implicationsfor the future management of the woods because future woodsmay not develop with the characteristics of the current stands,and may not be stable over time. 相似文献
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在蚂蚁河上游小流域以落叶松为试验树种进行不同立地因子造林试验,结果表明：不同地类上落叶松的地径、树高和近3年高生长量均以荒山荒地最高;落叶松树高生长以东坡和北坡最高,地径生长以南坡最大;暗棕壤上落叶松生长最好;土壤厚度与落叶松的各个生长量指标存在紧密的正相关关系。 相似文献
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水源涵养林结构与功能耦合关系模型研究——以北京山区水源涵养林为例 总被引：3，自引：1，他引：2
采用野外调查和数学模拟方法,选择树种组成、年龄、郁闭度、起源、层次、生物量以及土壤厚度等7个林分结构因子,建立了北京山区水源林结构与功能耦合关系模型。利用结构与功能耦合关系模型,比较了北京密云水库上游8种水源林森林类型,结果表明:1)保持水土功能大小顺序是阔叶混交林>桦树林>蒙古栎林>山杨林>油松林>刺槐林>侧柏林>落叶松林;2)涵养水源功能大小顺序是山杨林>蒙古栎林>桦树林>阔叶混交林>落叶松林>侧柏林>油松林>刺槐林;3)改善水质功能大小顺序是桦树林>蒙古栎林>山杨林>阔叶混交林>侧柏林>刺槐林>油松林>落叶松林。 相似文献
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采用H2O2溶液对落叶松表面进行活化处理的研究 总被引：2，自引：0，他引：2
为提高用水性高分子异氰酸酯胶粘剂(API)胶接的落叶松木材的胶接性能,采用H2O2溶液对落叶松表面进行活化处理.试验结果表明采用H2O2溶液处理落叶松木材表面可以提高其胶接强度,用H2O2溶液处理过的落叶松表面比未处理过的落叶松素材的常态压缩剪切强度提高15%.文中还讨论了采用H2O2溶液对落叶松表面进行活化处理可以提高其胶接强度的主要机理.通过傅立叶红外吸收光谱(FTIR)证明用H2O2溶液处理落叶松木材表面可以提高其常态压缩剪切强度的机理主要是氧化作用,即用H2O2溶液处理落叶松木材表面后,其表面或获得活性基团羰基.通过对其表面接触角的测定可以看出,H2O2溶液处理过的落叶松表面润湿性增加,这对胶接有利. 相似文献
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Jian-Zhang Li Takeshi Furuno Sadanobu Katoh Tohru Uehara 《Journal of Wood Science》2000,46(3):215-221
Acetylated, propionylated, butyrylated, isobutyrylated, and hexanoylated woods were prepared at several temperatures. The reaction rate, dimensional stability, and changes in the ratios of specific gravity and dimensions in the tangential and radial directions were estimated. The reaction rate of propionylation was slow at temperatures under 90°C but increased with the temperature. The butyrylated, isobutyrylated, and hexanoylated woods showed little or no weight percent gain (WPG) and little or no antiswelling efficiency (ASE) below 110°C even for 24h, but they achieved significant WPG and ASE values at 140°C with a longer reaction time. The acetylated, propionylated, and butyrylated woods showed almost the same values for dimensional stabilization efficiency based on WPG (DSE). The specific gravity and dimensions ratios for acetylated, propionylated, and butyrylated woods compared to those of untreated wood increased with an increase in WPG. 相似文献
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The Impact of Large Herbivores on the Conservation of Semi-natural Woods in the British Uplands 总被引：3，自引：0，他引：3
This review considers the history of woodland grazing and thegrazing ecology of large herbivores in the context of the conservationof semi-natural woods in the British uplands. The impact thatgrazing has on natural regeneration is frequently highlightedbut its effects on other vegetation, particularly the balancebetween bryophytes and higher plants are equally important.Grazing also influences both invertebrate and vertebrate populationsthrough its effect on vegetation structure. A low level of grazingby large herbivores in woodland provides a greater diversityin vegetation structure and species composition than eitherthe current prevalence of overgrazing or the absence of grazingin fenced woods. Low levels of grazing may also create conditionsfor the highest diversity of both plants and animals. The practicalproblems of managing woodland grazing are addressed in relationto conservation objectives for upland woods. Rotational grazing,seasonal grazing and reducing the overall levels of grazingin a wood are identified as possible management options. Furtherwork on these is however needed and topics for future researchare identified. 相似文献
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为了解燕山北部山地华北落叶松人工林植被物种多样性维持功能的高低，选取13a和30a生人工落叶松林，以13a和28a生天然次生杨桦林作为对照，对两种林分的植被多样性进行调查和分析，并研究了间伐对人工落叶松林植被物种多样性的影响。结果表明，林龄相同或相近的两种林分类型相比，无论是乔木层、灌木层或是草本层，人工落叶松林丰富度、Simpson指数、Shannon—Weiner指数均表现出相当或略高于天然次生杨桦林（30a生人工落叶松林乔木层多样性指数除外）；间伐对人工落叶松林植被物种多样性的短期影响主要体现在乔木层，对林下灌木层和草本层无明显影响。燕山北部山地人工落叶松林具有较高的植物多样性维持功能，没有导致物种多样性的降低。 相似文献
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万石头村风水林植被调查 总被引：2，自引：1，他引：1
狮山镇万石头村后的风水林是南海区目前保存比较好的地带性天然次生林,探讨其树种组成和群落结构,对生态公益林中的针叶人工林改造为生态效益高的季风常绿阔叶林,具有树种选择和配置模式的参考意义。 相似文献
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调查合肥市市郊5座城市山体的林分组成与群落结构,共记录样方66个。结果表明:山体林主要组成种有97种,分属49个科、82个属;主要优势种是侧柏、杉木、马尾松、朴树、麻栎等;林分平均密度1 384株/hm2,平均基盖度23.35 m2/hm2,平均胸径12.44 cm,平均高度11.08 m。群落类型可归纳为5个植被型、14个群系及34个群丛。主要植被型有落叶阔叶林、常绿与落叶阔叶林、针叶林等。树木整体较为健康,但景观效果欠佳,部分区域林分结构不够合理。建议引进乡土树种,特别是一些观赏树种,如栎、榆、椴、榉、黄连木、槭树等,来提升景观效果,增加生物多样性,完善生态功能。 相似文献