海东市青海云杉主要有害生物调查及防控对策

青海云杉是青海省主要的乡土针叶树种,也是海东市天然分布的水源涵养林重要组成树种。青海云杉也适宜人工种植,但近年来其有害生物越来越多,影响了长势。通过对海东市青海云杉有害生物的调查,危害海东市青海云杉的有害生物有12种,隶属3界5门5纲7目7科11属。其中松皮小卷蛾和高原鼢鼠在人工林危害较重;云杉丹巴腮扁叶蜂、黄腹阿扁叶蜂在天然林危害较重。为了增强林分的可持续控灾,通过调查研究,提出了几种有效防控措施。     

祁连山保护区林业有害生物防治

祁连山水源涵养林是河西地区水资源的贮蓄中心,在河西地区社会经济发展中起着举足轻重的作用,是河西走廊人民生存发展的命根子。由于祁连山区气候干旱,林区人为活动频繁,林分树种单一,森林生态系统失衡,森林病虫害常年暴发成灾,对森林生态系统健康构成了巨大的危害。随着保护区退耕还林、天然林保护、生态公益林建设等林业生态工程的全面实施,保护区森林资源面积逐年扩大,森林保护的任务越来越重,这就要求保护区必须加强林业有害生物防控工作,提高有害生物防控水平,有效保护森林健康,以促进保护区的可持续发展。目前,甘肃祁连山国家级自然保护区发生危害的森林害虫主要有云杉梢斑螟、松点卷蛾、异色卷蛾、云杉阿扁叶蜂、丹巴腮扁叶蜂、云杉多露象甲。发生危害的主要林木病害为青海云杉叶锈病、云杉落针病、云杉叶枯病、山杨黑斑病、山杨叶锈病、桦木     

气候因素对云杉阿扁叶蜂影响的初步调查分析

通过１９９１－１９９５年调查观测，分析了云杉阿扁叶蜂（ＡｃａｎｒｈｏｌｙｄａｐｉｃａｃｏｌａＸｉａｏｅｔＺｈｏｕ）发生，发育与空气温度，湿度的关系，得出自然变温下卵的发育起点温度为１．０３℃卵期有效积渐常数为３５４．５５日度，幼虫发育起点温度为３．１℃，有效积温常数为３２５．４７日度；并概述了降水，风，光对该虫活动的一般影响。     

云杉阿扁叶蜂危害损失测定

调查了云杉阿扁叶蜂不同食叶强度时青海云杉的侧枝，胸径生长量，建立了针叶损失率与虫口密度，侧会生长量，胸径生长量相对损失率之间的相关数学模型，级方差分析和多重比较划分了受害等级，为指导防治提供了依据。     

靖远松叶蜂生物学特性及发生因素分析

在靖远县哈思山自然保护区对靖远松叶蜂的生物学特性及影响其发生、发展的环境因素进行了观察研究。结果表明：该虫在靖远县哈思山林区主要危害油松,1年发生1代,以茧内预蛹幼虫在枯枝落叶层下、杂草基部或其它地被物下越冬,少量预蛹幼虫在树枝上结茧越冬。靖远松叶蜂的发生与林分因子、地形地势关系密切,发生程度一般表现为疏林重于密林,纯林重于混交林,长势弱的林分重于长势好的林分,阳坡重于阴坡。     

云杉阿扁叶蜂危害损失测定

调查了云杉阿扁叶蜂不同食叶强度时青海云杉的侧枝、胸径生长量,建立了针叶损失率与虫口密度、侧枝生长量、胸径生长量相对损失率之间的相关数学模型,级方差分析和多重比较划分了受害等级,为指导防治提供了依据。     

云杉阿扁叶蜂发生期预测研究初报

本文采用抽样调查与林间观察相结合的方法，观测了云杉阿扁叶蜂Ａｃａｎｔ－ｈｏｌｙｄａｐｉｃｅａｃｏｌａｘｉａｏｅｔｚｈｏｕ在祁连山大黄山林区的发育进度和各虫态历期，据此可进行一般发生年的发生期测报。根据几年来的防治经验，提出了不同卵密度情况下孵化盛期及应采取防治的时机与施药次数。     

云杉阿扁叶蜂研究初报

云杉阿扁叶蜂(Acantholyda piceacola),属膜翅目,扁叶蜂科,阿扁叶蜂属,是我国新发现种。该虫1983年首次在甘肃张掖地区山丹县大黄山林场发现,危害青海云杉(Picea cassifolia)为食叶害虫。据调查,成灾林区有虫株率100％,虫口密度970～12,000多头/株。蔓延很快,1983年危害150亩,1985年已蔓延到3,500亩。为害严重林分的林木针叶被食尽,枝上结满虫巢(见照片),林木处于濒死状态,严重影响了林木的生长和发育。经四年观察研究,兹将该虫的生物学特性及防治方法整理如下:     

中国扁叶蜂及叶蜂各一新种(膜翅目:扁叶蜂科、叶蜂科)

本文所记云杉阿扁叶蜂在甘肃张掖地区严重危害青海云杉Picea crassifolia,面积达4000亩左右;大麻毛怪叶蜂在安徽六安地区为大麻Cannabis sativa重要害虫,近年来常大发生。所有模式标本均保存在北京中国林业科学研究院林业研究所昆虫标本室。 1.云杉阿扁叶蜂Acantholyda piceacola新种雌虫(图1):体长12—13mm。触角柄节黄色,第2节深黄色,第3节以上愈向上愈黑。头部黑色;触角侧区黄色,唇基、内单眼眶大部分、鄂眼距、上唇、上颚除内缘、须、颊均深黄色。颈片深黄色。胸部黑色;前胸背板后缘及两侧、中胸前盾片后端、中胸小盾片后     

云杉阿扁叶蜂卵分布规律及抽样技术的研究

经抽样调查与统计分析，云杉阿扁叶蜂的卵７５％产于２年生针叶上，７８％的卵为１枚针叶关生１粒卵。卵在单株不同冠向间分无差异。卵的单株垂直分布因树冠各层针叶数量多少而呈现明显差异：树冠各层针叶健全时，卵集中产于下冠层；下层针叶稀少，而中上层针叶健全时，卵集中产于中冠层；中下冠叶均稀少时，卵则集中于产于上冠层。     

Effects of deforestation on microbial diversity in a Siberian larch(Larix sibirica) stand in Mongolia

For evaluating microbial community changes in a Siberian larch stand disturbed by forest fire or clearcutting,357 clones were randomly selected and sequenced using a culture-independent approach and 16S rRNA sequencing to characterize the bacterial composition and diversity from the different disturbed Siberian larch stands.Interestingly,the burned larch stand had an increase in the relative amounts of b-proteobacteria and Firmicutes and a decrease in Acidobacteria,while Gemmatimonadetes increased Verrucomicrobia decreased in the harvested larch stand.Microbial diversity and richness were higher in the undisturbed larch stand than the disturbed(burned or clear-cut)larch stands,and the influence of clear-cutting was more negative than that of the forest fire.This study indicates that evaluating the microbial diversity of undisturbed,burned,and clear-cutting Siberian larch stands provides information about the impact of forest disturbances on soil microbial communities,which may be helpful for understanding and evaluating soil health and devising reafforestation strategies for larch.     

Some reactions of<Emphasis Type="Italic"> Ips typographus</Emphasis> (L.) (Col.: Scolytidae) to changing breeding conditions in a forest decline area in the Sudeten Mountains,Poland

Investigations on I. typographus populations were conducted in 1992–1994 in the Sudeten (south-western Poland), in Norway spruce stands that were devastated previously by insect outbreaks and that exhibited severe forest decline. Crown defoliation and the volume of infested trees per hectare were used as indices of stand health and breeding conditions; variability in the infestation density, gallery length, and body length of beetles were parameters that were used to estimate the response of I. typographus populations to changing stand conditions. In stands located in the zone above 800 m a.s.l. where both the level defoliation and tree mortality were higher, the infestation density and body length of I. typographus were higher than in the zone below 800 m a.s.l., where stands were less damaged. Contrarily, the gallery length was higher in lower montane zone, where lower infestation densities and body length values were found. A proposed mechanism for this interaction, which is attributed mainly to better breeding conditions for I. typographus populations in weakened stands, is presented and discussed.     

Types of bark beetle (Coleoptera: Scolytidae) infestation in spruce forest stands affected by air pollution, bark beetle outbreak and honey fungus (Armillaria mellea)

583 spruce stands in an area affected by air pollution and bark beetle outbreak in Eastern Slovakia were studied in 1996. According to bark beetle infestation of dominant and codominant trees, stands were classified into following types of spruce stand decline:Ips typographus-A,Ips typographus-B,Polygraphus poligraphus, I. typographus/P. poligraphus—A,I. typographus/P. poligraphus—B. The presence of attacked trees in forest edges, bark beetle spots and forest interior was the key important factor for the classification. Data from forest inventory and forest management evidence together with data on types of spruce stands decline were used in further analyses. Results shows that the distribution of forest stands classified into different types or uninfested stands is related mainly to host size and site quality. The percentage of spruce, exposition of stands and stand density showed significant effects. The mechanisms of spreading of studied bark beetle outbreak could be explained by direct effects of stress of trees caused by an abrupt increase of level of solar irradiation and by weakening of trees by the honey fungus.     

Recent spruce decline with biotic pathogen infestation as a result of interacting climate,deposition and soil variables

Decline or health deterioration of Norway spruce (Picea abies (L.) Karst.) dominated forest stands has recently been observed mainly in sub-mountainous parts of Central Europe. Forest inventory of 208 randomly distributed circular plots including field observations of spruce tree health and rot symptoms by honey fungus (Armillaria ostoyae) was used for assessing intensity of spruce forest health decline in a managed forest area of 12.7 th. ha located in Beskids Mts., NE Czech Republic. First, principal component analysis was used to separate inventory variables related to environmental stress (reduced apical increment, dry tree top and stem resin exudation due to A. ostoyae infestation) into PC1, and health deterioration symptoms associated with mechanical damage (peeling, crown breaks) into PC2. The first two principal components explained 59% of the total variability in health decline symptoms. Spatial variability of both principal components was explained using spatial lag regression model identified from a set of environmental variables including sulfur and nitrogen deposition, elevation, solar radiation, age of the forest stands and geological properties (geochemical reactivity index). Environmental stress (PC1) was associated with low elevations (sub-optimal for spruce), high level of nitrogen and sulfur deposition (their interaction), low geochemical reactivity and also stand age. On the other hand, mechanical damage (PC2) significantly increased with elevation and stand age. As the forest decline in Beskids Mts. is related to A. ostoyae spreading from local infestation hot spots, both principal components had a significant spatial autocorrelation, partly distorting the signal of environmental conditions. The results indicate that the disturbed forest soils by long-term acid deposition and subsequent nutrient degradation and more pronounced drought stress at low elevations are the most important drivers of the recent spruce health decline in Beskids Mts.     

Forest structure classes in central Finnish Lapland

Structure classes and changes in the vegetation attributable to the altitude of the terrain were studied in the Hammastunturi virgin coniferous forest area. The area is located in Finnish Lapland, approximately 250–350 km to the north of the Arctic Circle (68°15'N; 68°45'N). The following forest classes were formed on the basis of the ground vegetation and stand coverage: (1) Pine stands, with birch admixture (n=14), (2) Vaccinium‐vitis‐idaea‐type pine stands (n = 24), (3) Vaccinium myrtillus‐type pine stands (n = 17), (4) mixed stands, dominated by pine (n = 8), (5) mixed stands, dominated by spruce (n=18), (6) paludified spruce stands (n = 3) and (7) vigorously growing spruce stands (n = 6). The forest structure classes were depicted using DCA ordinates. The differences were more distinct than those between the normal forest type classifications of the same sample plots. The basal area and volume of pine decreased with increasing altitude, while the proportion of spruce on those sample plots where it was present increased. Birch was present at an equal frequency at all altitudes. The floral composition and between‐species abundance changed along with increasing altitude. The change in floral frequencies could not be designated to a specific altitude zone.     

Is insecticide spraying a viable and cost-efficient management practice to control pine processionary moth in Mediterranean woodlands?

Insect pests are a major threat to many forests worldwide, from boreal to tropical forest ecosystems. Some pests exhibit periodical outbreaks, after which their populations often crash as a result of natural biological control. To offset such outbreaks, several management techniques are used, including aerial spraying of insecticides. The question remains whether pest decline following an outbreak is the result of management practices or a natural consequence of the insect's population cycle. In this study, we assessed the performance of aerial spraying of insecticides on pine woodland stands to control pine processionary moth Thaumetopoea pityocampa (PPM) outbreaks in southern Spain. To achieve this, we compared the degree to which a forest stand recovers from defoliation from one year of severe damage by PPM to the following year (infestation index) in stands that were treated (i.e. subjected to aerial spraying) and untreated using a 4-years database from the Regional Environmental Council. The results revealed a significant similar recovery from infestation after a PPM outbreak of both sprayed and non sprayed pine woodland stands, for the four most representative pine species (black, Aleppo, maritime, and stone pine). It is concluded that insecticide spraying cannot be considered a prevention for outbreaks if it is applied once the outbreak explodes. Management practices that can help control PPM outbreaks include promoting spatial heterogeneity at the landscape level, fostering biodiversity in pine plantations, and reinforcing parasitoid insect and predatory bird populations that negatively affect the PPM. This study illustrates how simple sampling designs and statistical tests can be useful decision-making tools and can help improve the environmental viability and cost-efficiency of forest management practices.     

绿竹丰产林培育的技术措施

文章介绍了绿竹丰产林培育的主要技术措施。幼林的管理措施主要有幼林管护、除草松土、施肥、母竹留养、间作套种；成林管理措施主要有扒土、施肥、培土、灌溉、绿竹采笋、母竹留养及合理采伐以及病虫害防治。     

洛南县松阿扁叶蜂危害现状与防治对策

松阿扁叶蜂(Acantholyda posticalis Matsumura)以取食油松、赤松、樟子松针叶危害,繁殖快,食量大,危害严重,近年在陕西秦岭东段及商洛市各县油松纯林中发生严重,洛南受害油松林面积达3万多hm2,加强对松阿扁叶蜂的防治工作迫在眉睫。     

青海云杉种实害虫发生危害研究

青海云杉种实害虫的主要种类为云杉球果小卷蛾,主要发生于天然林及母树木,虫害株率高达100%.-般低海拔林分重于高海拔林分,老母树林重于新母树林,纯林、疏林重于混交林和郁闭林分,远离天然林的种子园没有种实害虫的发生.在同一坡面上,随坡位升高虫害减轻,平缓林分重于陡坡林分,不同坡向间差异不明显;干燥林分重于湿润林分.平均单果虫口密度3头左右时,虫害果较健康果相比,出种率下降2.5%,健饱种数下降18.3%,虫蛀种子率达16.2%,千粒重下降0.93g,发芽率降低28%.