环保型染料染色技术在杨木单板染色中的应用

针对当前木材染色工业中酸性染料对木材的上染率较低,造成染色废水色度高、处理难度大的现状,选用固色率高、水解低和适合环保要求等优点的含双活性基团的M型活性染料三原色对杨木单板进行染色正交试验,作极差分析确定了速生人工林单板的活性染料染色的较优工艺条件:染色温度为70～80℃,染色时间3 h,元明粉40g.L-1,固色剂纯碱20 g.L-1,其中染色温度对活性染料杨木单板上染率的影响最大,其次是促染剂用量、染色时间和固色剂用量。在较优的工艺参数下对杨木单板进行染色试验,上染率分别为:活性红M—3BE 67.8%、活性黄M—3RE 68.6%、活性蓝M—2GE 58.9%,均大大高于酸性染料对木材的上染率(一般在30%以下)。这种染色方法降低了排放的染色废水中的染料,为速生人工林杨木的节能、环保染色提供了一条新的途径。     

电子显微观察下木材染色机理的对比性研究

将桦木单板作为研究对象,采用酸性染料和活性染料作为染色剂进行染色处理,并使用电子显微镜对染色单板进行显微观察;从而对单板的染色机理进行对比性研究,为木材染色技术的研究提供理论依据。通过研究发现,酸性染料和活性染料在木材中的存在方式有很大差异。酸性染料只是与木材发生了物理结合,而活性染料可以与木材发生化学反应,生成共价键结合。     

人工林毛白杨木材解剖构造与染色效果相关性的研究

为探讨木材构造和木材染色效果之间的相关性变化规律，本研究测字５株３４块人工林毛白杨 的解剖构造及其木材染色效果，对二者的相关性进行了多元回归分析。结果表明，毛白杨木材染色效果与解剖因子之间有一定的相关关系，各染色效果指标与木材解剖因子间的复相关系数在０．４８３６－０．７９９８之间，采用比较多元回归分析标准回归系数的方法，确定了影响毛白杨木材染色效果的主要解剖因子为导管比量、木纤维比量和木射线量等因子。     

低温等离子体处理对老化杨木单板染色性能的影响

研究了老化杨木单板低温等离子体改性后的染色性能。试验结果表明:未老化和老化杨木单板染色后,老化杨木单板表面染色均匀性变差,上染率、水洗色牢度明显降低。老化杨木单板经低温等离子体处理后,染色的均匀性得到改善,上染率提高,但水洗色牢度降低。     

乙酰化处理对樟子松木材耐光性和热稳定性的影响

【目的】探讨乙酰化处理对人工林木材耐光性和热稳定性的影响,为木材颜色调控技术及高耐光染色木材的研发提供理论依据。【方法】以樟子松木粉为试样,加入乙酸酐和二甲苯溶液,在120℃条件下分别反应5,10,20,40,60 min,测试乙酰化处理时间对木粉增重率的影响;分别称取1 g经不同时间乙酰化处理的木粉和未处理木粉,置于 UV老化试验箱内辐射100 h,利用红外光谱分析 UV辐射前后乙酰化木粉化学官能团的变化,通过热重和扫描电镜分析乙酰化木粉的热稳定性及其形貌变化。【结果】随着乙酰化处理时间的延长,樟子松木粉的增重率呈现先增加后降低的趋势,在处理40 min 时木粉增重率最大;乙酰化木粉在1741 cm －1和1385 cm －1处的CO,C—H特征吸收峰强度均大于原木粉,处理时间40 min 时木粉的吸收峰强度最大;UV 辐射后,乙酰化木粉在1508 cm －1处木质素苯环特征吸收峰强度明显大于原木粉,处理时间40 min 时木粉的吸收峰强度最大,表明木粉经乙酰化处理后光稳定性得到提升;热重分析显示,经乙酰化处理后,木粉热分解所需的温度明显提高,表明乙酰化木粉的热稳定性好于原木粉;扫描电镜分析表明,乙酰化处理可增强木粉微观构造抵抗光劣化的能力。【结论】乙酰化处理能有效抑制樟子松木材的光降解反应并提升其热稳定性。     

壳聚糖前处理染色木材耐光性的研究

对壳聚糖前处理与未处理（对照）染色木材耐光性的研究表明,山杨等６种壳聚糖处理与未处理木材用同一染料染色并辐射１０小时后,处理材色差均比未处理材低;经壳聚糖前处理与未处理的安息香木才,用四种不同染料染色,染色材耐光性优于未处理材,但随染料种类不同略有差异。     

染色工艺对桉木单板上染率的影响探究

为改善桉树单板材色,用酸性橙为染色试剂对漂白弦切桉木单板进行染色,选取NaCl质量分数、酸性助剂质量分数、染料质量分数、染色温度和染色时间为工艺参数,进行桉木单板染色试验和上染率测定。结果表明:在本试验条件下,染料最佳质量分数为0.01%、NaCl最佳质量分数为0.2%、酸性助剂最佳质量分数为0.1%、最佳时间为4h、最佳染色温度的为70℃,此时,桉木单板的上染率最好。     

壳聚糖前处理提高木材表面染色效果的研究

本文采用壳聚糖对木材表面进行前处理后，然后按不同树种，同一染料和同一树种，不同染料两种方式进行染色试验。结果表明：不同树种壳聚糖处理与未处理材的染色效果相比，处理材染色均一，没有色斑，颜色浓深，木材纹理清晰，当采用酸性红Ｇ染色，处理材明度减小，色饱和度增加，色差和色相差变化均很大；同一树种的处理材用不同染料染色，效果不同，亮色系染料染色效果较暗色系染料好。     

抽提预处理对木材的热重分析研究

为探究不同抽提方式对木材热解特性的影响,以云南松(边材和心材)为原材料,通过热水、丙酮、苯醇以及NaOH溶液抽提预处理,利用热重分析方法研究了不同预处理方式对木材热解失重特性的影响。结果表明:云南松心材与边材热解特性是不一致的;经NaOH溶液处理云南松及西南桦样品热解失重率较对照材较低了13%左右,可见经过低浓度NaOH溶液处理后木材增加了木材的残碳率,低浓度NaOH溶液处理使得木材生成一定量的酚类和酮类组分;经有机溶剂及热水处理虽加快了热解反应的进行,但对热解失重率影响不大。     

木材染色研究

通过酸性染料对低质木材单板进行染色对比试验研究，提出酸性染料对川滇恺木、滇杨、西南桦木等低质阔叶材有较好的易染性，并对影响染色工艺的因素进行了初步探讨，实验认为在70－80℃，PH及加入1．5％的均染剂后染色效果最佳。     

壳聚糖单凝聚法制备超细胶囊研究

阐述单凝聚法制备胶囊机理、一般工艺过程,并采用天然高分子物质壳聚糖为壁材,维生素E(VE)为芯材,通过单凝聚法制备胶囊,最佳条件为芯壁比1∶1,乳化时间30 min,乳化搅拌速度7 500～9 000 r/min,乳化剂MMAS用量6.0 %,固化剂用量为壁材的2倍,低温固化60 min.胶囊为球体,体系分相明显,其粒度0.10～3.00 μm,且粒度比较均匀、分布范围窄,具有较好的耐热强度、稳定性和分散性.     

羧甲基魔芋葡甘聚糖/壳聚糖凝胶化性能研究

羧甲基魔芋葡甘聚糖 /壳聚糖通过改变共混比例制备了混合凝胶 ,当多糖总质量分数为 4 %、盐离子浓度为 1 .6mol·L-1时 ,羧甲基魔芋葡甘聚糖对壳聚糖的共混质量比为 2 0 /80 ,在 70℃共混并恒温 30min ,可达凝胶强度最大值 ;研究了制备温度、恒温时间、体系中盐离子浓度及壳聚糖粘均分子质量与脱乙酰度对凝胶化影响。同时从FT IR谱图上分析了这两种多糖凝胶化作用机理     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Boron in forest trees and forest ecosystems

This review critically examines the role of boron (B) in forests in view of recent findings on B nutrition and the continuing occurrence of B deficiency. Many perceptions about the role of B in plants and its uptake and mobility have been altered since the last review on B in forest trees in 1990. Now there is evidence for a fundamental role of B in the formation of the pectic structure in primary cell walls in plants, and further roles in membrane function are being explored. In plants, channel-mediated B uptake, active B uptake and B uptake by mycorrhizas have been shown, B transporters have been identified, and B retranslocation has been shown. We explore these findings and their consequences on forest trees and on ecosystems that they dominate. Particular emphasis is placed on B retranslocation and B in mycorrhizal symbiosis, given their importance in trees.