松瘤象生物学特性初步观察

松瘤象幼虫危害马尾松活立木，在渝北区1a发生1代，以幼虫在被害树木质部越冬。翌年5月上旬开始化蛹，下旬始见成虫，6月上旬为成虫羽化高峰期，中旬为产卵盛期，幼虫孵化后即危害马尾松活立木的韧皮部及木质部表层，以后逐渐向木质部危害。可利用成虫具有较强趋光性的特性，设灯诱杀成虫；幼虫危害期对受害木进行拔除销毁，可降低虫口密度；加强检疫，防治人为传播。     

甘肃线小卷蛾生物学特性

甘肃线小卷蛾主要以幼虫危害油松当年新芽，在甘肃兴隆山国家级自然保护区人工油松林内普遍发生，被害林木顶梢枯黄呈火烧状。此虫1a发生1代，以卵在当年生针叶上越冬；翌年5月中旬开始孵化，5月中、下旬为孵化盛期；幼虫4龄，5月中旬到7月中旬幼虫危害新芽，蛹期7月上旬到8月中旬；8月上旬开始羽化，中旬为羽化盛期；8月中、下旬为产卵盛期，9月上、中旬进入越冬状态。6月中旬，用2．5％敌杀死乳油5000倍液喷雾，防治效果在95％以上，用40％亚胺硫磷乳油1000倍液喷雾，防治效果90％左右；羽化期可利用黑光灯诱杀成虫。     

榆锐卷叶象甲生物学特性及防治方法

榆锐卷叶象甲以成虫和幼虫危害榆树叶片，在辽宁省抚顺地区1年发生1代，以成虫在地被物或表土层中越冬。翌年5月中旬开始活动并危害嫩叶，6月上旬为产卵盛期，6月中旬幼虫孵化，幼虫卷叶危害，致使整树树冠悬挂黑褐色枯死的卷叶，6月下旬化蛹，7月上旬至中旬达羽化高峰，成虫于7月下旬、8月上旬进入越冬状态。5月下旬用2．5％溴氢菊脂4000倍液或2．5％功夫乳油3000倍液，喷雾防治效果均在95％以上；7月下旬或翌年5月上旬，用拟除虫菊酯制成的毒笔，在树干基部涂两个闭合环，毒杀成虫。     

侧柏生态防护林双条杉天牛生物学特性观察及防治对策研究

双条杉天牛在滕州主要1a发生1代(占75%),少数2a发生1代(占25%)。以当年羽化的成虫在树干木质部边材的蛹室内越冬(两年发生一代的以当年幼虫在木质部虫道内越冬),翌年2月中旬气温达10℃以上时成虫开始在树皮上咬一扁圆形孔钻出;3月中旬至4月上旬为出孔盛期;3月下旬为产卵盛期,卵历期14～18d;4月上旬为孵化盛期。5月上旬幼虫开始蛀入木质部内,1a发生1代的幼虫历期150d左右,2a1代的幼虫历期510d。9月上旬为化蛹盛期,蛹历期18～20d。9月下旬为羽化盛期。采取生物、化学、物理、营林等综合防治技术,有效地控制该虫的危害,达到长期有虫不成灾,实现森林健康。     

黄缘阿扁叶蜂生物学特性及防治研究

黄缘阿扁叶蜂Acantholyda flavomarginata Maa在赫章危害华山松.该虫1a发生1代,以老熟幼虫在土中越夏越冬,翌年3月中旬开始化蛹,4月上旬始见成虫并产卵,4月中旬幼虫孵化,5月下旬幼虫开始下树入土,进入越夏越冬状态.4月中旬为成虫羽化、产卵盛期,4月中、下旬为幼虫孵化盛期.4月中、下旬为防治幼虫最佳时期.采用30%氯马乳油1500倍液树冠喷药,12 h虫口死亡率达90%以上.     

松扁叶蜂在野河林区防治方法

松扁叶蜂在我国危害油松,是油松重要害虫之一,松扁叶蜂一年发生一代,以老熟幼虫入土越冬.在野河林区4月中旬至4月底开始化蛹,5月上旬为化蛹盛期,同时,成虫开始羽化,5月中下旬为羽化盛期,同时开始孵化,6月上旬为孵化盛期也是危害盛期,6月底7月初,幼虫开始下树,下旬全部下树越冬.     

桉树油桐尺蛾生物学特性及防治试验

在福建省仙游县开展桉树林油桐尺蛾的生物学特性观察与防治试验,结果表明:在福建仙游油桐尺蛾1 a发生3代,以蛹在土里越冬;翌年4月上旬—中旬成虫开始羽化,4月下旬为羽化盛期;第1代幼虫5月上旬孵出,5月下旬开始结茧化蛹,6月上旬成虫羽化,6月中旬为羽化盛期;第2代、第3代幼虫分别在7月上旬、9月中旬孵化,第3代幼虫10月下旬结茧化蛹进入越冬状态。采用溴氰菊酯烟雾剂进行应急化学防治可迅速降低虫口,灭幼脲Ⅲ号1 000倍液喷雾防治可控制该虫的危害。     

榛实象甲生物学特性及发生特点研究

榛实象甲是危害平榛的主要害虫,在辽宁省铁岭市2年发生1代,少数为3年1代。常以老熟幼虫及成虫在寄主植物附近的土壤中越冬。5月上旬越冬成虫出土,6月中下旬雌成虫产卵于幼果内,7月上中旬为产卵盛期,7月中下旬为孵化盛期,幼虫在果内取食近1个月后发育成老熟幼虫。老熟幼虫8月下旬~9月上旬入土越冬。入土的幼虫下一年7月下旬化蛹,7月下旬至8月下旬新成虫羽化,8月中旬为成虫羽化盛期。新羽化的成虫直接入土越冬。阳坡榛林比阴坡受害重,山下比山上受害重,纯林比混交林受害重,林龄越高受害越严重。     

北京地区白蜡窄吉丁生物学特性研究

白蜡窄吉丁(Agrilus planipennis Fairmaire)是一种危害白蜡的重要蛀干害虫。该虫在北京大兴地区1a发生1代,以老熟幼虫在韧皮部与木质部之间的边材坑道内越冬。4月上旬开始化蛹,4月中旬为化蛹高峰,4月底成虫开始羽化,5月中旬为羽化高峰。5月下旬成虫开始产卵,6月中旬幼虫孵化,持续到7月上旬孵化结束。     

松尺蠖生物学特性与防治方法

松尺蠖(B up a lus p in ip aria L innaeus)是鳞翅目、尺蛾科的一种危害云南松、华山松针叶的害虫。在盐源县一年发生1代,以幼虫在树干周围土壤中越冬。翌年2月上旬开始活动,3月中旬至5月下旬幼虫取食危害盛期,6月下旬幼虫下地化蛹,8月中旬为成虫羽化始期,8月下旬至9月中旬为羽化盛期,9月下旬至10月上旬成虫羽化产卵结束,产后三周左右卵孵化出幼虫,9月下旬到翌年2月中旬为幼虫越冬期。其防治措施为卫生抚育、物理防治、化学药剂防治、生物防治和灯光诱杀防治。     

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.     

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.     

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.     

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。     

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.     

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.