使用烟雾机防治落叶松尺蛾试验

利用多种化学药剂使用烟雾机防治落叶松尺蛾(Erannis ankeraria Staudinger),试验表明,40倍4%高效氯氰菊酯乳油柴油烟剂防治落叶松尺蛾,成本低,效果好,优于其他几种药剂.     

苏特灵Bt生物杀虫剂防治春尺蛾的试验

应用苏特灵Bt生物杀虫剂防治春尺蛾，其毒力效价≥8000IU/mg,800倍液防治春尺蛾，室内72h校正杀虫率97．0％，林间72h校正杀虫率96．8％，持效期14d，杀虫率78．7％，是理想的除治春尺蛾的生物杀虫剂。     

黄刺蛾的防治技术研究

为了有效控制黄刺蛾(Cnidocampa flavescens Walker)的为害,用10%杀虫葳、40%氧化乐果、4.5%高效氯氰菊酯、25%灭幼脲和1.8%阿维菌素等5种药剂的不同浓度对黄刺蛾进行室内毒力测定和圃间防治试验,并对结果作方差分析。室内外试验结果表明:所选用的5种药剂和浓度对防治效果均有显著影响;林间防治以10%杀虫葳4000倍液喷雾效果最佳,杀虫效果达90%以上。     

桉树油桐尺蛾室内化学防治技术研究

以25%灭幼脲粉剂(增效型)、25%阿维菌素.灭幼脲悬浮剂、5%吡虫啉乳油、AS-2型杀虫乳剂四种化学药剂进行油桐尺蛾室内防治试验,结果表明:4种药剂对油桐尺蛾4龄幼虫具有较好的杀虫效果。25%灭幼脲粉剂(增效型)和AS-2型杀虫乳剂具有较好的杀虫速效作用;5%吡虫啉乳油具有较好的杀虫缓效作用;25%阿维菌素.灭幼脲悬浮剂兼具速效和缓效作用,为生产防治的首选药剂。     

华北落叶松鞘蛾防治技术的研究

笔者研究了黑光灯、苦参素杀虫剂、药剂(1.8%阿维菌素乳油、1.2%烟参碱、25%灭幼脲)喷雾、0.9%阿维菌素喷烟4种华北落叶松鞘蛾的防治技术。结果认为,黑光灯诱捕对落叶松鞘蛾有一定的防治效果,但作用较为局限。1%苦参素植物杀虫剂对华北落叶松鞘蛾幼虫具有较好的防治效果,1∶1 000的效果最佳。1.8%阿维菌素乳油、1.2%烟参碱和25%灭幼脲喷雾均对华北落叶松鞘蛾具有较好的防治效果,1.8%的阿维菌素乳油效果最明显。0.9%阿维菌素地面喷烟对防治华北落叶松鞘蛾成虫效果较好,选择1.0∶25的配比较经济。     

辽阳地区木撩尺蛾危害成因及防治技术

田其有,黄永强(辽阳市森防站,辽宁辽阳　111000)　　木撩尺蛾(ＣｕｌｃｕｌａｐａｎｔｅｒｎａｒｉａＢｒｅｍｅｒｅｔＧｒｅｙ),又名木撩步曲、吊死鬼等,属鳞翅目尺蛾科。2000年8月,辽阳地区部分落叶松林突发木撩尺蛾危害,第2年发生面积进一步扩大,对落叶松林产生严重危害,大片落叶松林延缓、停止生长,部分树木出现枯枝或死亡,并引发其它虫害或病害发生。针对这一情况,我们对发生情况进行了调查和发生原因分析,并开展了防治工作。现将两年来的工作情况整理如下,供参考。1木撩尺蛾发生情况根据调查,2000～2001年木撩尺蛾在辽阳地区发生及经…     

桉树害虫油桐尺蛾林间防治试验

对桉树害虫油桐尺蛾幼虫进行林间药剂防治试验,结果表明:使用单剂生物药剂0.6%阿维菌素水剂4 000倍液、16 000 IU.mg-1苏云金杆菌粉剂1 000倍液喷雾防治幼虫,10 d后的防治效果达89%~97%;使用混合化学药剂A3B3C3、A2B2C3和A1B3C3这3种组合喷雾防治油桐尺蛾幼虫,7 d后的防治效果达84%以上;使用混合生物药剂a1b1c2、a1b3c3和a1b1c1这3种组合喷雾防治油桐尺蛾幼虫,10 d后的防治效果达80%~96%;使用烟雾剂柴油5 kg+20%氰戊菊酯乳油0.375 kg、柴油5 kg+20%氰戊菊酯乳油0.25 kg、柴油5 kg+20%氰戊菊酯乳油0.125 kg喷雾防治幼虫,7 d后的防治效果达89%以上。     

长治地区槐尺蛾的生活习性调查及其药剂防治试验

对山西长治地区槐尺蛾的生活习性进行了调查,查悉槐尺蛾在长治地区1年发生4~5代,并了解到其的生活习性。选用不同浓度的氧化乐果、灭扫利、溴氰菊酯、灭幼脲、辛硫磷、来福灵以及苏云金芽孢杆菌等药剂对槐尺蛾2、3龄幼虫进行了室内防治实验,其试验结果表明,应用3种常规浓度的化学农药来福灵、溴氰菊酯及生物药剂苏云金芽孢杆菌防治槐尺蛾幼虫的效果最佳。     

兴安落叶松鞘蛾不同虫态烟剂防治试验

杀虫烟剂防治落叶松鞘蛾的常规方法是：在成虫羽化盛期产卵这前，放烟熏杀成虫，缺点晨：有效防治时间短；不同林份的防治电动机不一致，不利于大面积组织防治，一次性施药的有效杀虫率低，在鞘 蛾越冬幼虫期利用烟剂防治能克服以下缺点，且防治效果也较明显。     

树干注射技术防治杨小舟蛾的研究

将40％久效磷可溶性农剂和50％甲胺磷乳油稀释成不同浓度后进行树干注射，定期采叶用杨小舟蛾Micromelatopha troglodyta Graeser幼虫进行室内生测试试验，结果表明，2种有机磷内吸杀虫剂对杨小盘蛾具有良好的杀虫效果，林间用浓度为200g/L的自配长效内吸注干乳油进行注射防治试验，结果1次防治保证了杨小舟蛾全年5代末发生灾情。     

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.     

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.     

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.     

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.     

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.