温室野蛞蝓的发生规律及综合治理技术的研究

本文介绍了温室有害软体动物野蛞蝓ＡｇｒｉｏｌｉｍａｘａｇｒｅｓｔｉｓＬ．的习性和危害特点，进行了综合防治试验。结果证明，填实育苗营养袋间的空隙防治效果达８９％；地面撒布呋喃丹３％颗粒剂，施用量８．３ｇ／ｍ＾２防治效果达８０％～９５％，方法可行，利于推广。     

板栗大圆筒象研究初报

板栗大圆筒象ＭａｃｏｃｏｒｙｎｕｓＰｓｉｔｔａｃｉｎｕｓ（Ｒｅｄｔ．）以成虫危害板栗叶片、严重时栗叶损失达８０％以上，减产２０％－４０％。该虫在皖南一年发生１代，以幼虫在栗林表土层中越冬。采用５０％甲胺磷乳剂、４０％氧化乐果乳剂２０００倍液喷雾，防治效果分别为９１．０１％和９６．２０％。用３％呋喃丹颗粒剂防治幼虫效果为６３．８６％。     

板栗大圆筒象研究初报

板栗大圆筒象ＭａｃｏｃｏｒｙｎｕｓＰｓｉｔｔａｃｉｎｕｓ（Ｒｅｄｔ）以成虫危害板栗叶片、严重时栗叶损失达８０％以上，减产２０％－４０％，该虫在皖南一年发生１代，以幼虫在栗林表土层中越冬。采用５０％甲胺磷乳剂，４０％氧化乐果乳剂２０００倍液喷雾，防治效果分别为９１．０１％和９６．２０％，用３％呋喃丹颗粒剂防治幼虫效果为６３．８６％。     

白僵菌与氰戊菊酯混用防治马尾松毛虫的初步研究

该研究应用白僵菌粉剂与０．４％氰戊菊酯粉剂按４∶１比例混合均匀后，加工成粉炮防治马尾松毛虫ＤｅｎｄｒｏｌｉｍｕｓｐｕｎｃｔａｔｕｓＷａｌｋｅｒ，每ｈｍ２放粉炮３０个，每个炮重１２５ｇ，经室内和林间试验以及大面积推广防治，平均防治效果达９０％以上，较纯菌粉粉炮防治有明显的增效作用，平均防效提高１５．３％，害虫感病流行时间提前７天以上；较采用纯０．４％氰戊菊酯粉粉炮防治效果提高２８．８％，能及时有效地控制高虫口林分松毛虫的严重危害，减少松针损失４０％以上，经济效益和生态效益显著     

德昌松毛虫质型多角体病毒防治大柏毛虫应用研究

应用德昌松毛虫质型多角体病毒ＤｅｎｄｒｏｌｉｍｕｓｐｕｎｃｔａｔｕｓｔｅｃｈａｎｇｅｎｓｉｓＣｙｔｏ－ｐｌａｓｍｉｃＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓ（ＤｐｔＣＰＶ）防治四川内地柏木林区大柏毛虫Ｄ．ｈｏｕｉＬａｊｏｎ－ｑｕｉｅｒｅ的试验表明，以７．５×１０９ＰＩＢ／６６６．６ｍ２以上剂量防治３龄幼虫，其综合防效达８５％以上，且具有显著的扩散流行和持续防治效果。     

油桐尺蛾危害大面积水杉林的调查及防治

１９８８年９月底上海市崇明县东平林场１５３．３ｈｍ２１５年生水杉人工林遭到油桐尺蛾ＢｕｚｕｒａｓｕｐｐｒｅｓａｒｉａＧｕｅｎｅｅ严重危害。经调查研究和防治试验，该虫在崇明地区一年发生２代，应用油桐尺蛾核型多角体（ＢＳＮＰＶ）＋青虫菌防治效果达９０．１％，一次防治控制多代，至今没有复发     

斑鞘豆叶甲的生物学特性和防治研究初报

斑鞘豆叶甲ＰａｇｒｉａｓｉｇｎａｔａＭｏｔｓｃｈｕｌｓｋｙ危害白三叶草等多种豆科植物，近年来在河南省焦作市绿地、草坪猖獗成灾，一年发生２代，幼虫在土中越冬，翌年３月下旬开始化蛹、羽化，成虫食叶为害。８月下旬出现第２代成虫，这代幼虫危害至秋后在土中越冬。成虫期喷洒４０％氧化乐果１０００－１５００倍液或故杀死５０００倍液，防治效果达９０％以上．     

国外松枯梢病防治试验

对国外松枯梢病Ｄｉｐｌｏｄｉａｐｉｎｅａ（Ｄｅｓｍ）Ｋｉｃｋｘ．作施硼和药剂防治试验，晶体硼砂３０克／株的效果最好，平均防治效果８０．４％。其次是２２１００波尔多液为７６．５％，４０％多菌灵４００倍液为５９．３％，７０％甲基托布津４００倍液为５９％。营林措施防治效果为６５．８％—６６．２％。     

德昌松毛虫质型多角体病毒防治大柏毛虫应用研究

应用德昌松毛虫质型多角体病毒Ｄｅｎｄｒｏｌｉｍｕｓ ｐｕｎｃｔａｕｓ ｔｅｃｈａｎｇｅｎｓｉｓ Ｃｙｔｏｐｌａｓｍｉｃ ＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓ防治四川内地柏木林区大柏毛虫Ｄ．ｈｏｕｉＬａｊｏｎｑｕｉｅｒｅ的试验表明,以７．５×１０＾９ＰＩＢ／６６６．６ｍ＾２以上剂量防治３龄幼虫,其综合防效达８５％以上,且具有显著的扩散流行和持续防治效果     

化学农药对白僵菌的影响及菌药合用的初步研究

化学农药对卵孢白僵菌Ｂｅａｕｖｅｒｉａｂｒｏｎｇｎｉａｒｔｉ菌丝生长、孢子萌发的影响及对蛴螬毒杀剂量筛选的研究试验表明，６０％３９１１、５０％辛硫磷和对硫磷乳油使用浓度＞５０ｐｐｍ时，白僵菌的菌丝生长和孢子萌发受到明显的抑制。２％林丹颗粒剂使用浓度＜１００００ｐｐｍ对白僵菌无明显影响。３．５％的３９１１颗粒剂同白僵菌在苗床上分层施用，防治淡翅黎丽金龟ＢｌｉｔｏｐｅｒｔｈａｐａｌｉｄｉｐｅｎｎｉｓＲｅｉｔｅｒ幼虫，效果达９８．６％，比单独使用３９１１防治效果提高１８．６％。     

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.     

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.     

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.     

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.     

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。