不同地理种源思茅松对松实小卷蛾抗性调查

调查结果显示：思茅松林木受松实小卷蛾危害后对树高生长影响较大，高生长平均损失量为0．50m，其高生长损失率平均为16．40％；对林木径生长影响不大，反而能促进径生长，促进径生长量平均为0．11cm。提高径生长率平均为3．63％。经分析在35个思茅松种源中对松实小卷蛾抗性较强的种源有通关、木乃河8^#、木乃河11^#和曼歇坝1—18^#等11个种源。     

松实小卷蛾对几种碳烯醛的室内行为反应研究

通过松实小卷蛾雄蛾对(E)-2-癸烯醛、(E)-2-十二碳烯醛、(E,E)-2,4-癸二烯醛和(E,E)-2,4-十二碳二烯醛4个化合物的室内行为反应实验。结果表明,4个化合物都可在一定程度上引起松实小卷蛾雄蛾的兴奋、起飞、定向飞行等反应;松实小卷蛾雄蛾对(E,E)-2,4-癸二烯醛的反应最为强烈,是松实小卷蛾信息素的关键组分,其余3个化合物也是其信息素中不可或缺的组分。能够引起松实小卷蛾雄蛾明显行为反应的最低刺激量为0.01μg。     

我省外引松主要梢果害虫寄生蜂的调查观察

调查结果表明:我省外引松主要梢果害虫的微红梢斑螟、松实小卷蛾、油松球果小卷蛾的寄生蜂共有26种。其中寄生于微红梢斑螟的16种、松实小卷蛾的10种、油松球果小卷蛾的2种、在为害枝梢的微红梢斑螟、松实小卷蛾上的寄生率达13.2%,在为害球果的微红梢斑螟上寄生的主要是广大腿小蜂,平均寄生率达15.7%。经鉴定的寄生蜂12种,隶属于茧蜂、姬蜂、小蜂、广肩小蜂、扁股小蜂、肿腿蜂6个科。并分别对6个科的寄生蜂的分布和主要特征以及生物学特性作了阐述。     

思茅松纯林及针阔混交林中松实小卷蛾和微红梢斑螟诱捕量比较研究

在思茅松纯林和针阔混交林中,以(E,E)-2,4-癸二烯醛、(Z)-11-十六碳烯乙酸酯为引诱剂,对松实小卷蛾和微红梢斑螟进行了诱捕试验。结果表明,以(E,E)-2,4-癸二烯醛为引诱剂,在思茅松纯林和混交林内平均每个诱捕器分别诱捕到松实小卷蛾6.30头和3.10头;以(Z)-11-十六碳烯乙酸酯为引诱剂,在思茅松纯林和混交林内平均每个诱捕器分别诱捕到微红梢斑螟3.60头和2.40头;混交林内的松实小卷蛾和微红梢斑螟的诱捕量显著少于纯林。     

松实小卷蛾室内行为和室内饲养

研究了松实小卷蛾Retinia cristata雌蛾在室内的求偶行为和不同日龄雌蛾的求偶高峰,发现松实小卷蛾的求偶高峰出现在黑暗期后的3~5 h,在羽化后的第2 d和第3 d求偶行为最为强烈。同时,探索了松实小卷蛾的室内饲养方法。     

松实小卷蛾在云南生活史及其对思茅松的危害

松实小卷蛾Retinia cristata Walsingham在云南危害思茅松是个新发现。2001-2003年对其生活史进行了观察。松实小卷蛾在思茅地区1a发生3代，以幼虫在受害梢中越冬。该虫主要危害2～3a生幼林，同一株树以向阳面受害最重，受害枝梢的直径范围为4．7～13．0mm。     

松实小卷蛾的危险性分析

松实小卷蛾是对我国松属植物造成严重危害的一种蛀梢、蛀果害虫。为正确认识松实小卷蛾对林木的危害性,加强对其管理,有效地控制该虫的危害,防止其进一步的扩散蔓延,采用有害生物危险性分析的方法,对松实小卷蛾在我国的危险性进行了系统的定性与定量相结合的分析。通过此综合评估,认为松实小卷蛾在我国属中度危险性的森林有害生物。     

思茅松无性系种子园松实小卷蛾的诱捕试验

在2008年7月至8月,以顺-7-十二碳烯-1-醇和反-9-十二碳烯-1-醇为引诱剂,对位于云南西双版纳州景洪市普文的思茅松无性系种子园的主要球果害虫松实小卷蛾的成虫进行了诱捕试验.试验结果表明,这2种化合物对松实小卷蛾的雄蛾有显著的引诱作用,可依据含有这2种化合物的诱芯的诱捕器连续捕获松实小卷蛾雄蛾数量变化的态势对松实小卷蛾害虫的虫情进行监测.     

南亚松种子园无性系成活率及生长性状分析

以南亚松(Pinus latteri)种子园嫁接无性系为研究对象,分析南亚松无性系的成活率和生长性状,为南亚松种质资源保存、种子园营建及良种选育提供参考。结果表明,南亚松种子园不同种源的无性系成活率在28%～88%之间,平均58.5%。海南和越南种源无性系的平均成活率高于防城港。3个种源南亚松嫁接株的平均接穗高生长量、接穗径生长量、冠幅和主干分枝数分别为91 cm、31.32 mm、73 cm和5,不同指标间均呈极显著正相关(P 0.01)。成活率大于70%的17个无性系间对比分析表明,越南无性系的生长优于海南无性系;多重比较分析表明来自越南的11#和13#无性系生长最优。     

松实小卷蛾的研究进展

简要综述了松实小卷蛾寄主及分布、生物学特性、虫害发生与环境的关系、天敌资源及防治技术等方面的研究进展,以期为松实小卷蛾的发生与防治提供技术参考。     

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.     

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.     

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.     

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.     

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。