阿拉善盟梭梭林鼠害防治试验初报

利用不同药剂、饵料及投药方法 ,对梭梭林大沙鼠进行防治试验。采用堵洞法检验防治效果 ,筛选出最佳药剂为猫王 (1∶ 1 5 0 ) ,C·肉毒杀鼠素 (1 ml) ,最佳饵料是胡萝卜 ,最佳投药方法是洞口投药 ,为森林鼠害治理工程大面积推广提供了科学依据     

东阿拉善自然保护区天然梭梭林鼠害防治技术

对东阿拉善自然保护区天然梭梭林害鼠种类、密度、危害情况进行调查,并进行人工地面防治试验和飞机防治试验。从调查结果可看出天然梭梭林害鼠种类有20种,以大沙鼠为优势种,春季危害严重,秋季次之。试验结果表明:C型肉毒素(1∶80∶1000)防治效果最佳,并且成本较低,饵料选择为胡萝卜,投药方法为洞口投药,投药时间为每年为3~4月份;飞机防治试验没有取得理想效果。     

人工投放地芬·硫酸钡饵剂防治梭梭林大沙鼠试验初报

应用人工洞口投放20.02%地芬·硫酸钡饵剂对阿拉善左旗地区梭梭林大沙鼠进行适口性和药效试验。结果显示:投药后6 d,大沙鼠对20.02%地芬·硫酸钡饵剂的消耗率为98.40%;投药后10 d,投药量为每洞口6,8,10 g的处理区校正有效洞口减退率分别为75.70%,86.94%,82.19%,捕获率减退率分别为50.00%,50.00%,69.23%;每洞口8 g处理区的校正有效洞口减退率显著高于6 g处理区;未发现非靶标动物中毒死亡。大沙鼠对该药剂的适口性良好;在阿拉善左旗地区人工投放20.02%地芬·硫酸钡饵剂以每洞口8～10 g为宜。     

木材害虫熏蒸技术的应用与研究

１９９１～１９９３年，针对巴盟地区林木蛀干害虫危害严重的实际，在推广应用磷化铝熏蒸处理技术的同时，开展了不同投药量和熏蒸时间的对比试验，选择最佳投药量及熏蒸时间，杀虫效果均达到１００％，经济效益显著。     

果实标本的制作与保存

果实的形状、大小、果色等,是果树栽培品种的重要经济指标。为使果实标本完好的保存,便于今后进行鉴定、评比和研究,我们在原有标本制作技术的基础上,参阅了大量资料,对果实标本进行了多次制作试验。掌握了不同树种、不同品种、不同颜色及不同成熟度果实标本的制作方法。制作的     

蜡叶标本保绿制作技术

植物病害蜡叶标本的一般制作方法是将新鲜标本叶片夹在标本纸中,通过不断更换标本纸,使其逐渐脱水干燥,成为蜡叶标本。这样制作的标本,保存1～2年后,叶片的绿色会逐渐褪去,变成枯黄色,使病害症状不再明显,影响对病害的观察与识别。现介绍几种使植物病害蜡叶标本保持     

小型鸟类假剥制标本制作新方法

鸟类假剥制标本有制作简单、易于储藏、查检方便、利于交流等优点。笔者在小型鸟类假剥制标本制作中,曾做了一些新的尝试,主要有如下几点: 1、在标本剥制过程中,要想求得简便、节省时间,最大的障碍是头骨上肌肉的剔除,若剔不干净,会使标本易腐败,易受     

竹类植物标本馆的综合防虫研究

竹类植物标本在一般室内条件下极易受蠹虫类害虫侵食,一旦受损害,珍贵的标本无法修复而失去保存价值。因此防治害虫是竹类植物标本馆管理事务中一项很重要的工作。作为我国收藏标本种类最全和数量最多的竹类专业标本馆之一,浙江省林业科学研究院竹类标本馆自1981年建馆以来采取"以防为主,综合防治"的措施。除了随手关好门窗和标本柜,以阻隔害虫侵入外,还从新增标本进行严格的消毒处理;定期定量在标本柜放置天然樟脑;一发现虫害苗头,及时进行全馆化学熏蒸杀虫等措施进行防治,取得了良好的效果,使标本得以长久保存。     

龙竹的机械、热和微观结构分析

在龙竹竹杆的3个不同高度取材加工成竹条,并浸泡在蒸馏水中,记录竹条的老化时间,分析龙竹条的抗弯机械性能。对于未加工的竹条,抗弯性能并不随着秆高而变化。相对于未老化的标本,老化的标本的断裂模数降低,并且从秆底部到秆上部减少。同时,通过对未老化标本和老化标本的比较,老化标本的抗弯模数也呈下降趋势,但对于取自同一部位且浸泡时间相同的标本而言,抗弯模数没有变化。利用光学显微技术和数字图象处理技术对杆不同部位的微观结构的变化进行评估。利用镶嵌技术分析横切面,这能够测量大量纤维的数量。结果表明,从数据来讲,在杆的各个高度,主要结构参数(如单位面积的纤维数量)无变化。然而,不同部位的纤维形态有所不同,在杆上部可发现更长的纤维。可用热解重量分析法确定龙竹的热性能。热降解过程中在单阶段发生,并于280.10C开始。在此过程中,可获得166KJ/mol的活化能。     

昆虫标本的制作

昆虫是动物界最大的一个类群 ,全世界已知有 1 0 0多万种 ,而我国分布有 1 5万多种 ,还有相当多的昆虫有待发现或命名。野外采集的昆虫标本要及时制作 ,妥善保存 ,以供科学研究、教学和生产参考 ,昆虫标本也是一笔宝贵的资源。制作昆虫标本 ,不但要保持虫体各部分特征完整 ,还要求美观、整洁。1　针插标本的制作把成虫用昆虫针插起来 ,装盒入柜保存。昆虫针由不锈钢制成 ,分 7种型号 ,其中 0 0型为二重针 ,只有 1 cm长 ,顶端无针帽 ;0～ 5号针均 4cm长 ,顶端用铜丝做成针帽 ,针越粗型号越大。针插标本制作时 ,应根据虫体的大小选择适当的昆…     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

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.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

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.     

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

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.     

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.     

CAD与建筑设计的关系

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。     

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.     

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.     

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.