靖远松叶蜂危害损失量研究

靖远松叶蜂是为害油松的一新种叶蜂,油松受害后,生长和发育受到影响,当针叶被取食95％以上时,可使油松生长率降低10．1％,连续2a-3a严重为害,可导致林木死亡。     

新松叶蜂的发生也防治

新松叶蜂,又名松黄叶蜂,属松叶蜂科。主要危害油松、赤松、华山松、马尾松、黑松、红松、云南松等松属的针叶。2005—2007年,祁门县马尾松受其侵害,幼虫大量取食针叶,严重影响马尾松的正常生长。     

新松叶蜂的发生与防治

新松叶蜂,又名松黄叶蜂,属松叶蜂科。主要危害油松、赤松、华山松、马尾松、黑松、红松、云南松等松属的针叶。2005～2007年,祁门县马尾松受其侵害,幼虫大量取食针叶,严重影响马尾松的正常生长。一、分布与危害情况新松叶蜂在我国主要分     

新松叶蜂的发生与防治

新松叶蜂,又名松黄叶蜂,属松叶蜂科。主要危害油松、赤松、华山松、马尾松、黑松、红松、云南松等松属的针叶。2005～2007年,祁门县马尾松受其侵害,幼虫大量取食针叶,严重影响马尾松的正常生长。一、分布与危害情况新松叶蜂在我国主要分     

新松叶蜂的发生与防治

新松叶蜂,又名松黄叶蜂,属松叶蜂科。主要危害马尾松等松属的针叶。马尾松受其侵害,幼虫大量取食针叶,严重影响马尾松的正常生长。     

广西新松叶蜂生活习性观察及其防治

广西新松叶蜂(Neodiprion guangxiicus Xiao et Zhou)属膜翅目、广腰亚目、松叶蜂科,分布广西(博白)、四川(盐源)、云南(南华、呈贡、丽江、永仁、广南、昆明、江川、宣威)。幼虫取食云南松针叶,食料不足时,亦取食华山松针叶,大发生时针叶被食光,余下枝梢及枝干,生长受到严     

松阿扁叶蜂的预防与治理

松阿扁叶蜂隶属于膜翅目,广背叶蜂总科,扁叶蜂科。主要危害油松、樟子松、赤松等树种的叶子。松阿扁叶蜂以幼虫取食针叶,大发生时针叶受害率达80%以上,枝梢上布满残渣和粪屑,林分似火烧一般。松阿扁叶蜂成虫多集中在晴天羽化,有补充营养的习性,在针叶上取食形成小缺刻。成虫受惊后落地假死,不久即飞翔逃跑,夜间不活动,对白光(日光灯)亦无反应。松阿扁叶蜂发生量     

靖远松叶蜂生物学及发生规律的研究

靖远松叶蜂（Ｄｉｐｉｏｎ ｊｉｎｇｙｕａｎｅｎｓｉｓ）是危害油松的重大森林害虫，１９９４年定为新种。该文对其形态、生物学特性、与环境因子的关系及主要天敌作了深入研究。此虫在山西省沁源，一般一年１代，以芯内预蛹（拟）在落叶层下越冬，成虫于６月间大量出现，少数有滞育现象，两年完成１代，雌雄性比为１：０．６每雌产卵１２０粒～２２９粒，有孤雌生殖现象，幼虫共８龄，每头幼虫取食针叶６０根左右、纯林、疏林、阴坡虫口密度大，靖远松叶蜂病毒（ＮＰＶ）、白僵菌、金头赘寄蝇、大山雀等２２种天敌是制约该虫种群数量的重要环境因素。     

南华松叶蜂的发生与防治

南华松叶蜂（Diprion nanhuaensis Xiao）属膜翅目、叶蜂总科、松叶蜂科。主要是以幼虫取食针叶，一头幼虫一生可取食针叶700cm左右，危害云南松、华山松、马尾松。通过10多年的观察与防治试验研究，基本摸清了南华松叶蜂的生活史、生物学特性、发生规律及综合防治技术．为南华松叶蜂的防治提供了科学依据。     

强优防治手段 加大科技含量 我省靖远松叶蜂防治工作取得重大突破

靖远松叶蜂是我省新发生的森林病虫害之一,去年,我省集中力量对交城、文水、沁源县和关帝林局境内发生的靖远松叶蜂(原名油松桦叶蜂)实施了飞机低容量喷雾防治和地面人工施放烟雾剂防治,取得了重大突破。防治面积共25.14万亩,其中飞机作业112架次,防治22万亩;地面施放烟雾剂16.7吨,防治3.14万亩。经效果检查,飞防区平均虫口减退率达97.4％,烟雾剂杀虫效果也达90％以上。我省靖远松叶蜂防治工作主要采取了以下措施:一、领导重视,精心组织。去年,各级政府和林业部门对靖远松叶蜂防治工作非常重视。针对我省大面积暴发靖远松叶蜂虫灾的情况,姜春云副总理明确指示:“要迅速采取措施扑灭虫灾”;林业部徐有芳部长、     

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.     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.