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采用主要成分为氯化锌、磷酸二氢铵及复合铜盐(硝酸铜+醋酸铜)的三种药剂对马尾松和桉树木材做浸渍处理后再进行短周期加热处理的方法,研究了处理工艺对热处理木材失重率和耐腐性能的影响。结果表明:处理木材的失重率和耐腐性能均随着处理温度升高和处理时间的延长而增大,氯化锌药剂热处理木材在较高温度下对木材的失重率影响最大,具有明显加速热处理反应的作用;但是在同样的热处理温度条件下,浸渍氯化锌和复合铜盐的热处理木材耐腐性明显优于未加药剂的热处理木材。三种药剂中,由复合铜盐浸渍处理的木材经190℃热处理后能达到强耐腐等级。 相似文献
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随着人类环境意识的提高,某些对环境和人体健康有较大影响的木材防腐剂(如铬化砷酸铜CCA)的使用受到限制或禁止。除了开发新的环保型木材防腐剂外,木材改性处理作为木材保护的另一手段,它在提高木材耐腐性方面的研究日益受到关注。本文主要介绍了木材改性处理的方法及防腐机理,并综述了国内外关于木材化学改性处理(以及热处理)后木材的耐腐性(以及抗虫蚁性)方面的研究现状,指出了我国在利用改性方法提高木材耐腐性方面研究所存在的问题,展望了今后研究和发展的方向。 相似文献
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我国主要树种的木材(心材)天然耐腐性试验 总被引：3，自引：0，他引：3
木材天然耐腐性是木材本身固有的抗腐朽能力,各种树种的耐腐性不尽相同,它与木材特性组织结构及其内含物的化学成分有关。从木材利用的要求来说,希望木材具有良好的耐腐性能,经久耐用。但各种木材的天然耐腐性很不一致,为了合理利用我国森林资源,在木材利用上既可考虑选用耐腐树种,也可对不耐腐树种的木材进行必宴的防腐处理,以增强木材的耐腐性,延长木材使用年限。做到合理利用木材和培植优质耐腐树种。尤其在当前我国四个现代化的建设中,木材需用量激增,但在我国森林资源不足的情况下,对于木材耐腐性的试验研究,是迫切需要解决的课题之一,同时,也可为我国生产、科研、教学提供必要的科学依据。本试验选用161种树种木材进行了室内天然耐腐性试验。为了得到比较完善的结果,对部分树种的木材还进行了不同木腐菌(包括白腐菌与褐腐菌)的耐腐性比较试验。 相似文献
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文章以马尾松、尾叶桉、马占相思和南洋楹4种木材为研究对象,采用KJQ、TRQ、WAQ 3种涂料与防腐剂复配处理木材,研究复配涂料对木材耐腐性能的影响。结果表明KJQ复配涂料处理对提高马尾松的耐腐性能较其它2种涂料好。经KJQ复配涂料处理后,马尾松、尾叶桉、马占相思和南洋楹木材的耐腐性能由原来的稍耐腐等级提高到强耐腐等级,其中KJQ涂料与DDAC、IPBC和SGB 3种防腐剂活性成分复配后的处理材耐腐性能较好。 相似文献
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主要综述了季铵盐类化合物(QAC)在用作木材防腐剂时的耐腐性、抗流失性及其与木材的结合机理等方面的研究概况,分析了实验室耐腐性和野外实验耐腐性结果不一致的原因。此外也介绍了对季铵盐进行改性处理方面的一些研究进展。 相似文献
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载药聚丙烯酸/聚乙二醇半互穿聚合物网络在木材中的原位构建及其性能 总被引：1，自引：0，他引：1
《林业科学》2016,(11)
【目的】在木材中原位构建载药半互穿聚合物网络体系,以提高木材耐腐性,改善木材的尺寸稳定性。【方法】以丙烯酸为单体,过硫酸铵为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,在聚乙二醇存在下原位反应,一步法合成聚丙烯酸/聚乙二醇半互穿聚合物网络(PAA/PEG SIPN)。研究交联剂含量对聚合物性能的影响,并采用傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)对其结构和形貌进行表征。采用真空浸渍法将质量百分比为0.5%的丙环唑纳米制剂和反应物注入木材中,使其在木材内部进行原位反应并交联,测试处理后木材的尺寸稳定性和室内耐腐性。【结果】FTIR分析表明,PAA和PEG除形成氢键外,还能通过交联剂形成相对牢固的化学结合。SEM和TEM结果发现,聚乙二醇较均匀地分散在聚丙烯酸中,形成相互贯穿的网络结构。在一定范围内,随着交联剂含量的增加,聚合物的溶胀性能减弱,强度增大。相对于未处理材,处理材的干缩湿胀性得到明显改善。室内耐腐性试验表明,处理材的药剂抗流失性和耐腐性得到明显提高。【结论】本文所及处理方法能够在一定程度上提高木材的尺寸稳定性和防腐性能,虽然对尺寸稳定性的作用尚未达到理想状态,但可为木材的改性处理提供一种新思路。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
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本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):131-138
The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken. 相似文献
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Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic
or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts
(stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea
(Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content
as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest
N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized
to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea,
largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for
N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant
components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N
released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures
were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality
components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in
the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols.
Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest
age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its
components are mixed. 相似文献
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A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste
disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization,
(2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two
pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea
(Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect
on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage
sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but
affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献