大连市松材线虫病典型发生区松墨天牛种群动态

为了摸清松墨天牛的羽化高峰期,更好地防治松材线虫病,采用在典型样地悬挂诱捕器的方法,于2018年5-10月对大连市甘井子区、中山区典型样地的松墨天牛种群活动情况进行了调查。结果表明:样地发现松墨天牛、褐梗天牛和小灰长角天牛3种蛀干害虫;松墨天牛的羽化高峰期在6月末至7月上中旬,6-7月的虫口密度占全年的80%以上,为科学有效地监测松褐天牛的发生规律,预测松材线虫病的发生与及时有效地控制其蔓延提供科学依据。     

福建省泉州市松墨天牛的生活史与生物学特性

2015—2018年在福建省泉州市的南安罗山林场采用林间养虫笼仿野外饲养方法,系统观察松墨天牛的生活史和生物学特性。研究表明,松墨天牛在泉州地区1 a发生2代,部分1 a发生3代。松墨天牛多以高龄幼虫在蛀道中越冬,4月上旬始见成虫,5月中旬为越冬代成虫羽化出孔高峰期。第1代幼虫5月下旬可见,6月中旬开始蛀入木质部,7月中旬成虫羽化出孔,8月中旬为第1代成虫羽化出孔高峰期。第2代幼虫最早于8月中旬出现,多数以高龄幼虫在蛀道中越冬;有15.2%松墨天牛幼虫可发育为成虫并羽化出孔和交尾产卵,于11月上旬产生第3代越冬幼虫。研究结果可为松材线虫病的防治提供参考。     

喀左县褐梗天牛成虫羽化规律研究

为揭示褐梗天牛(Arhopalus rusticus)在喀左县发生规律,采用林间踏查、悬挂诱捕器的方法对喀左县油松林内褐梗天牛发生规律及特性进行调查分析。结果表明褐梗天牛在喀左县成虫期为每年4月底5月初至10月上中旬,每年有两个羽化高峰期,分别为6月中旬至8月上旬和8月中旬至9月下旬。试验结果为喀左县防治褐梗天牛,控制松材线虫病蔓延提供了参考依据。     

青岛地区褐梗天牛发生规律研究

为揭示褐梗天牛Arhopalus rusticus(Linnaeus)在青岛地区发生规律,采用林间踏查、设置诱捕器、解析枯死木的方法对青岛李沧地区黑松林内褐梗天牛发生规律及特性进行调查及分析。结果表明褐梗天牛在李沧成虫期为每年4月底5月初至10月上中旬,每年有两个羽化高峰期,分别为6月中旬至8月上旬和8月中旬至9月下旬。实验结果为青岛地区防治褐梗天牛甚至控制松材线虫病蔓延提供了参考依据。     

崂山区松墨天牛及褐梗天牛羽化规律研究

松墨天牛(Monochamus alternatus)及褐梗天牛(Arhopalus rusticus)是崂山地区重要的蛀干害虫,为有效的防治这两种天牛提供理论依据,本实验研究了这种天牛的羽化规律。松墨天牛羽化时段为5月上旬-7月中旬,其羽化高峰期集中在6月上旬-6月中旬,雌雄天牛羽化无明显差异。褐梗天牛羽化时段为5月上旬-7月下旬,羽化高峰时段集中在5月中下旬,7月中旬出现一次小的羽化高峰,雌雄天牛羽化无明显差异。     

松褐天牛的防治

松褐天牛是松材线虫传播的中间媒介,松材线虫疫区周围松褐天牛虫口密度直接影响松材线虫病的传播速度。防治不及时,可导致松材线虫病的蔓延。因此,要掌握松褐天牛成虫羽化、产卵、幼虫蛀食三个时期的生活特性,对做好松褐天牛危害防治工作极为有利。     

如何防治松褐天牛危害

松褐天牛是松材线虫传播的中间媒介,松材线虫疫区周围松褐天牛虫口密度直接影响松材线虫病的传播速度,不及时防治,可导致松材线虫病的蔓延。因此,要掌握松褐天牛成虫羽化、产卵、幼虫蛀食三个时期的生活特性,对做好松褐天牛危害防治工作极为有利。松褐天牛生活习性:1年1代,以老熟幼虫在坑道中或树孔内越冬。浙江5月初,越冬幼虫在虫道末端蛹室中化蛹。5月中旬成虫羽化,此时虫道中有成虫、蛹、幼虫同时存在。5月下旬成虫咬1个圆形羽化孔出树,取食幼枝嫩皮为补充营养。成虫喜在疏林、光线充足的林地内活动产卵。产卵时,先在病树或衰弱树干或枝…     

松墨天牛成虫羽化逸出及其携带松材线虫能力的研究

松墨天牛成虫是松材线虫病的主要传播媒介,研究其成虫羽化逸出规律及其携带松材线虫能力,在松墨天牛和松材线虫的监测和综合治理上具有重要意义。研究结果表明,松墨天牛成虫羽化逸出期和高峰期,平均每年分别为８３ｄ和１２．３ｄ。携带松材线虫的松墨天牛成虫平均寿命为２９．８ｄ。松墨天牛成虫全身均能携带松材线虫,其数量比率顺序为胸〉头〉腹〉触角〉足〉翅。在浙江省富阳市,林间采用引诱剂诱获的松墨天牛成虫,平均每头携     

几种诱杀松墨天牛方法的效果比较及评价

利用３种方法诱杀松墨天牛成虫的试验结果表明,松饵木能引诱到补充营养的松墨天牛成虫,且雌成虫能在松饵木上产卵,引诱剂对引诱怀卵的松墨天牛成虫的效果较好。引诱剂和松饵木使用方便、安全,成本较低,大面积应用可降低松墨天牛种群密度,减少松材线虫传播机会。但单独使用达不到防治松材线虫病的目标。灯光诱杀远不如引诱剂和松饵木,且其成本高,安全性差,用于松墨天牛防治不宜提倡。利用引诱剂和松饵木在监测松墨天牛及松材     

利用松褐天牛早期监测松材线虫病技术研究

在室内对因松材线虫病死亡马尾松树干羽化出的松褐天牛测定结果表明，８６％的天牛携带松材线虫，平均１头天牛携带３５９０条。林间引诱松褐天牛，在没有松材线虫病的健康林地，分离不到松材线虫，而松材线虫病发生区引诱到的天牛６５％携带松材线虫，携带量在１０１～５０００条之间。在５月下旬～６月中旬，应用黑光灯，新鲜马尾松木段，引诱松褐天牛１０头能上，采用松材线虫常规分离方法，可以早期监测松材线虫病的发生情况。     

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.     

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.     

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.     

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。     

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.