红塔山自然保护区切梢小蠹种群数量及危害调查研究

在红塔山自然保护区的灵照山片区和徐家山片区的云南松林中设置调查样地29个,对切梢小蠹种群、生物学特性及危害特征进行调查研究。结果表明,红塔山自然保护区发生的切梢小蠹主要有云南切梢小蠹和横坑切梢小蠹2种,在种群数量分布上以横坑切梢小蠹占优势,平均占78.30%。2种切梢小蠹同时存在于同一林分中形成交叉危害,对枝梢危害长度和树干危害部位存在明显差异。建议在切梢小囊蛀梢期及转干繁殖前及时采取措施降低虫口密度。     

云南省切梢小蠹种群结构及其演替规律

[目的]为明确云南省切梢小蠹种群结构及变化规律,指导切梢小蠹的防控。[方法]在云南蠹害林区调查采样并鉴定切梢小蠹种类,比较20世纪90年代和2010年代石林、安宁、丘北3地切梢小蠹种群结构及变化情况。[结果]共有4种切梢小蠹在云南发生危害,其中,横坑切梢小蠹占发生总量的38.1%,云南切梢小蠹占36.6%,松芽小蠹占19.7%,华山松切梢小蠹占5.6%。小蠹种群结构90年代与目前比较发生了显著变化,主要体现在横坑切梢小蠹和云南切梢小蠹,云南切梢小蠹所占种群数量由20世纪90年代的92.1%减少到目前的42.7%,而横坑切梢小蠹由20世纪90年代的7.9%,迅速增长到目前的57.3%。[结论]在云南,经过20年种群演替,之前云南切梢小蠹一支独大危害松林的局面,已转变为云南切梢小蠹和横坑切梢小蠹角力共同危害松林,预示当地松林尤其是云南松林正处于亚健康或不健康的状况,结果为云南省切梢小蠹的监测和防控提供了新的科学数据支持。     

云南松纵坑切梢小蠹种群生态研究现状

通过对现有文献的考察 ,从影响云南松纵坑切梢小蠹的危害因素 ,小蠹的生活史、蛀干蛀梢期、种群动态、生命表、空间分布格局以及虫情预测预报等方面阐述了云南松纵坑切梢小蠹种群生态的研究进展状况。以此对松小蠹的综合治理提出几点建议     

两种切梢小蠹生态学特性比较研究

纵坑切梢小蠹和横坑切梢小蠹是中国主要的森林蛀干害虫。在云南,两虫经常在云南松等松类树种上共同危害,造成重大生态和经济损失。这两种小蠹的种群结构因地区而异,其性比、成虫在枝梢上聚集危害的时间及其在树冠上的空间分布规律基本相同,但在树干上的空间分布规律有很大差异。通过研究并比较这两种小蠹的种群结构、性比、季节分布及空间分布等生态学特性差异,对防治有重要意义。     

山松大小蠹的危害及其治理

山松大小蠹又称黑山松大小蠹或落矶山松大小蠹,是北美西部危害最严重的小蠹,也是最严重的森林害虫之一,近年来在美国和加拿大周期性暴发成灾。主要介绍山松大小蠹的危害症状及危害性,生物学习性,气温、寄主、天敌、信息素对其种群的影响,与共生真菌及其他小蠹的关系等生态学习性。同时对山松大小蠹大发生原因以及综合治理措施等进行概述。     

云南松纵坑切梢小蠹种群生态研究现状

通过对现有文献的考察，从影响云南松纵坑切梢小蠹的危害因素，小蠹的生活史，蛀干蛀梢期、种群动态，生命表，空间分布格局以及虫情预测预报等方面阐述了云南松纵坑切梢小蠹种群生态的研究进展状况，以此对松小蠹的综合治理提出几点建议。     

信息素饵树技术在小蠹防治中的应用

本文着重介绍了信息素饵树技术在减少小蠹危害、控制小蠹种群扩散中的应用实例,并就人为诱导次期性小蠹对攻击性种类进行竞争取代的可行性进行评价。     

松十二齿小蠹成虫种群数量动态研究

应用"十二齿小蠹引诱剂"开展松十二齿小蠹成虫种群数量变化的研究。结果表明:松十二齿小蠹成虫种群数量总体呈下降趋势,雌雄比稳定,种群还可能继续下降。在研究分析成虫羽化规律的基础上,提出相应的防控建议。     

云南松抚育间伐试验林昆虫捕获量研究

在个旧白沙冲云南松抚育间伐试验林进行昆虫捕获量研究,共获得11个目的昆虫,其中鳞翅目、同翅目、半翅目及双翅目类为优势类群,占昆虫类群全捕量的74．59％,是该林区昆虫类群的主体。昆虫数量与不同强度间伐后的林分类型和该林分松纵坑切梢小蠹危害程度有一定关系,间伐林分昆虫种群密度高,昆虫捕获量大,松纵坑切梢小蠹危害很低;而不间伐林分,昆虫种群密度小,昆虫捕获量最少,松小蠹危害明显高于间伐林地。     

纵坑切梢小蠹综合防治研究

本文是纵坑切梢小蠹系统研究论文中的综合防治部分。文章根据多年的试验研究成果，首先提出了划分云南松林分蠹害程度及蠹害木的分级标准，针对林分的危害情况，采取相应的蠹害治理综合措施。蠹害治理的主要技术措施包括：１．蠹害木清理技术；２．化学农药防治技术；３．生物防治技术；４．小蠹聚集信息素引诱技术等内容。对小蠹提出了以营林技术措施为基础，清理蠹害木为主，合理施用化学农药，应用生物防治手段控制林间种群密度的防治策略     

Altitudinal differences in bark stripping by sika deer in the subalpine coniferous forest of Mt. Fuji

Deer expansion is a growing concern for forest ecosystem management. In Japan, upward expansion to subalpine and alpine areas has reached alarming proportions in recent years. We examined bark stripping by sika deer along an altitudinal gradient in the subalpine coniferous forest at three altitude ranges (1800-2000 m, 2000-2200 m, and 2200-2400 m) on the southern slope of Mt. Fuji. We tested differences in densities and diameter at breast height (DBH) of trees and those with bark-stripped stems of all tree species among the three altitude ranges. Then, we compared the relative densities of deer, based on pellet counts, to determine the impact of deer in relation to deer use and forest stand patterns across the altitudinal range studied. The results of the study show that differences in bark stripping by sika deer depended largely on the elevation and the species. Larger stems were sparsely distributed in the lowest elevation zone between 1800 and 2000 m. The relative density of deer was highest in the areas exhibiting high bark-stripping intensity on small regenerating trees of the dominant coniferous species, Abies veitchii, and on broadleaf species. In the highest elevation zone between 2200 and 2400 m, smaller stems were densely distributed, and the relative deer density was lowest where the bark-stripping intensity on small stems was lower for all three species studied. The damage to subalpine tree stems corresponded to the availability of palatable tree species with a small diameter, as reflected by the successional stage along the elevational gradient of subalpine forest on Mt. Fuji. These results suggest that the continuous impact of bark stripping on the dominant tree species might cause severe changes in forest succession.     

Predatory beetles in cacao agroforestry systems in Brazilian Atlantic forest: a test of the natural enemy hypothesis

The natural enemy hypothesis predicts a positive correlation between plant species diversity and natural enemy control. This study aimed to evaluate the role of traditional cacao agroforests, known as “cabrucas,” on the conservation of the predatory beetle community compared to that of monodominant rubber agroforests. Predatory beetles were sampled in three habitats in Southeastern Bahia, Brazil: cabrucas and rubber agroforests and native Atlantic forests. In each habitat, 18 10 m² plots were established, in which canopy cover was measured and beetles were sampled with a modified Malaise/window trap. Land use intensification did not affect the composition of predatory beetles, with the presence of widely distributed species that are also capable of colonizing simpler environments such as the rubber agroforest. Canopy cover had a positive effect on generalist predator diversity and we observed a reduction in the abundance and species richness of generalist predators with increasing habitat homogenization. Despite the simplified structure of the habitat, the remaining tree diversity and canopy cover in cabrucas supported a community of generalist predators similar to the one found in the native forest. Species diversity of bark beetle predators was higher in cabrucas, which may be due to the high diversity of bark beetles and the favorable abiotic conditions, whereas the low abundance of prey in the native forest and severe abiotic conditions in the rubber agroforest probably determined the lower diversity of generalist predators in these habitats. Cabrucas play an important role in the conservation, supporting a community of predatory beetles more similar to the one found in native forest and that is more effective at controlling populations of herbivores than in homogeneous rubber agroforests.     

三峡库区云阳县三种类型马尾松林微生物区系及优势种群分析Ⅱ.林地空气、叶面和树皮表面

为探讨马尾松不同类型林地地上部微生物区系及优势种群及其季节性变化,对三峡库区云阳县马尾松近熟龄天然林、中龄天然林和人工林林地空气、叶面和树皮表面等地上部的可培养细菌和真菌进行了分析。结果表明,空气、叶面和树皮表面的真菌、细菌两大类微生物数量四季变化趋势基本一致,夏季和秋季的数量多于冬季和春季,中龄天然林的两大类微生物数量最大且四季变化亦最大;优势种群的种类和数量随季节和林地类型不同而有所变化。人工林空气中可培养真菌种类秋、冬、春、夏分别有4、3、4、3种,近熟龄天然林和中龄天然林四季中均为3种;优势种群多     

太原市油松小蠹虫及其综合防控技术研究

小蠹虫是一类重要的森林害虫,多为次期性害虫。通过调查,在太原市为害油松的主要种类是松六齿小蠹、松八齿小蠹和松十二齿小蠹;成虫扬飞期分别出现在5月份、7月份、8月份、9月份,是防治的关键时期;引起小蠹虫成灾的原因除自然因素外,主要是人为因素,所以防控小蠹虫要以虫情测报为基础,以检疫和林木管护措施为主导,并辅以生物、人工、化学等综合防控措施。     

Carbon and nitrogen dynamics along the log bark decomposition continuum in a mesic old-growth boreal forest

Narrowing the uncertainties in carbon (C) and nitrogen (N) dynamics during decomposition of coarse woody debris (CWD) can significantly improve our understanding of forest ecosystem functioning. We examined C, N and pH dynamics in the least studied CWD component—tree bark in a 66-year-long decomposition chronosequence. The relative C concentration decreased by ca. 32% in pine bark, increased by ca. 18% in birch bark and remained stable in spruce and aspen bark. Nitrogen increased in bark of all tree species. In conifer bark, it increased along with epixylic succession. Over 45 years, the relative C/N ratio in bark decreased by 63 and 45% for coniferous and deciduous species, respectively. Bark pH did not change. Due to bark fragmentation, the total C and N amounts in bark of individual logs of aspen, birch, pine and spruce decreased at average rates of 0.03, 0.02, 0.26 and 0.05 year^?1, and 0.02, 0.02, 0.03 and 0.03 year^?1, respectively. At the forest stand level, the total amounts of C and N in log bark were 853 and 21 kg ha^?1 or 11.2 and 45.5% of the C and N amounts stored in downed logs and ca. 2.3–3.8 and 2.2–2.4%, respectively, of total C and N amounts stored in forest litter. In boreal forests, decomposing log bark may act as a long-term source of N for wood-inhabiting communities.     

Impact of bark beetle (Ips typographus L.) disturbance on timber production and carbon sequestration in different management strategies under climate change

The likely environmental changes throughout the next century have the potential to strongly alter forest disturbance regimes which may heavily affect forest functions as well as forest management. Forest stands already poorly adapted to current environmental conditions, such as secondary Norway spruce (Picea abies (L.) Karst.) forests outside their natural range, are expected to be particularly prone to such risks. By means of a simulation study, a secondary Norway spruce forest management unit in Austria was studied under conditions of climatic change with regard to effects of bark beetle disturbance on timber production and carbon sequestration over a time period of 100 years. The modified patch model PICUS v1.41, including a submodule of bark beetle-induced tree mortality, was employed to assess four alternative management strategies: (a) Norway spruce age-class forestry, (b) Norway spruce continuous cover forestry, (c) conversion to mixed species stands, and (d) no management. Two sets of simulations were investigated, one without the consideration of biotic disturbances, the other including possible bark beetle damages. Simulations were conducted for a de-trended baseline climate (1961–1990) as well as for two transient climate change scenarios featuring a distinct increase in temperature. The main objectives were to: (i) estimate the effects of bark beetle damage on timber production and carbon (C) sequestration under climate change; (ii) assess the effects of disregarding bark beetle disturbance in the analysis.Results indicated a strong increase in bark beetle damage under climate change scenarios (up to +219% in terms of timber volume losses) compared to the baseline climate scenario. Furthermore, distinct differences were revealed between the studied management strategies, pointing at considerably lower amounts of salvage in the conversion strategy. In terms of C storage, increased biotic disturbances under climate change reduced C storage in the actively managed strategies (up to −41.0 tC ha⁻¹) over the 100-year simulation period, whereas in the unmanaged control variant some scenarios even resulted in increased C sequestration due to a stand density effect.Comparing the simulation series with and without bark beetle disturbances the main findings were: (i) forest C storage was higher in all actively managed strategies under climate change, when biotic disturbances were disregarded (up to +31.6 tC ha⁻¹ over 100 years); and (ii) in the undisturbed, unmanaged variant C sequestration was lower compared to the simulations with bark beetle disturbance (up to −69.9 tC ha⁻¹ over 100 years). The study highlights the importance of including the full range of ecosystem-specific disturbances by isolating the effect of one important agent on timber production and C sequestration.     

Retention of aspen (Populus tremulae) at final cuttings - The effect of dead wood characteristics on saproxylic beetles

To preserve biodiversity in managed forest landscapes dead and living trees are retained at final cuttings. In the present study we evaluated the effect of these practices for saproxylic (wood-dependent) beetles inhabiting dead aspen trees (Populus tremulae). For saproxylic beetles, tree retention at final cuttings can be expected to be especially valuable for species adapted to sun-exposed dead wood, a substrate that only rarely occurs in well managed forest stands. Therefore, the current evaluation was conducted as a comparison of species richness, species density (number of species per sample), assemblage composition and occurrence of individual species between clear-cuts, where aspen trees were retained, and closed forest stands with aspen trees. The study was conducted in central Sweden and the beetles were sampled by sieving of bark from CWD (coarse woody debris) of aspen. There was no significant difference in rarefied species richness between forest and clear-cut sites. Species composition differed significantly between the two stand types. Generalized linear mixed-effects models predicted the species density to be 34% lower in CWD objects in forest sites than on clear-cuts. This pattern could partly be explained by differences in CWD diameter, decay class and bark types between the two stand types (clear-cut/forest). Stand type was a significant predictor of occurrence in individual CWD objects for 30% of analysed individual beetle species. For all species except one, the variable stand type predicted higher occurrence on clear-cuts than in forest stands. To conclude, our results demonstrate that retention of aspen on clear-cuts contributes to population recruitment of a different assemblage of species than CWD within stands.     

Transport,storage and mobilization of nitrogen by trees and shrubs in the wet/dry tropics of northern Australia

Xylem sap from woody species in the wet/dry tropics of northern Australia was analyzed for N compounds. At the peak of the dry season, arginine was the main N compound in sap of most species of woodlands and deciduous monsoon forest. In the wet season, a marked change occurred with amides becoming the main sap N constituents of most species. Species from an evergreen monsoon forest, with a permanent water source, transported amides in the dry season. In the dry season, nitrate accounted for 7 and 12% of total xylem sap N in species of deciduous and evergreen monsoon forests, respectively. In the wet season, the proportion of N present as nitrate increased to 22% in deciduous monsoon forest species. These results suggest that N is taken up and assimilated mainly in the wet season and that this newly assimilated N is mostly transported as amide-N (woodland species, monsoon forest species) and nitrate (monsoon forest species). Arginine is the form in which stored N is remobilized and transported by woodland and deciduous monsoon forest species in the dry season. Several proteins, which may represent bark storage proteins, were detected in inner bark tissue from a range of trees in the dry season, indicating that, although N uptake appears to be limited in the dry season, the many tree and shrub species that produce flowers, fruit or leaves in the dry season use stored N to support growth. Nitrogen characteristics of the studied species are discussed in relation to the tropical environment.     

Assessing forest vulnerability and the potential distribution of pine beetles under current and future climate scenarios in the Interior West of the US

The aim of our study was to estimate forest vulnerability and potential distribution of three bark beetles (Curculionidae: Scolytinae) under current and projected climate conditions for 2020 and 2050. Our study focused on the mountain pine beetle (Dendroctonus ponderosae), western pine beetle (Dendroctonus brevicomis), and pine engraver (Ipspini). This study was conducted across eight states in the Interior West of the US covering approximately 2.2 million km² and encompassing about 95% of the Rocky Mountains in the contiguous US. Our analyses relied on aerial surveys of bark beetle outbreaks that occurred between 1991 and 2008. Occurrence points for each species were generated within polygons created from the aerial surveys. Current and projected climate scenarios were acquired from the WorldClim database and represented by 19 bioclimatic variables. We used Maxent modeling technique fit with occurrence points and current climate data to model potential beetle distributions and forest vulnerability. Three available climate models, each having two emission scenarios, were modeled independently and results averaged to produce two predictions for 2020 and two predictions for 2050 for each analysis. Environmental parameters defined by current climate models were then used to predict conditions under future climate scenarios, and changes in different species’ ranges were calculated. Our results suggested that the potential distribution for bark beetles under current climate conditions is extensive, which coincides with infestation trends observed in the last decade. Our results predicted that suitable habitats for the mountain pine beetle and pine engraver beetle will stabilize or decrease under future climate conditions, while habitat for the western pine beetle will continue to increase over time. The greatest increase in habitat area was for the western pine beetle, where one climate model predicted a 27% increase by 2050. In contrast, the predicted habitat of the mountain pine beetle from another climate model suggested a decrease in habitat areas as great as 46% by 2050. Generally, 2020 and 2050 models that tested the three climate scenarios independently had similar trends, though one climate scenario for the western pine beetle produced contrasting results. Ranges for all three species of bark beetles shifted considerably geographically suggesting that some host species may become more vulnerable to beetle attack in the future, while others may have a reduced risk over time.     

丹江口库区主要森林类型树干茎流研究

对丹江口库区马尾松林、柏木林和栎类阔叶林3种主要森林类型及单木树干茎流特征进行了研究,结果表明:3种森林类型树干茎流率为0.58%～7.69%,树干茎流量与降水量成线性相关,回归方程达到极显著水平;不同树种间的树干茎流量差异显著,影响树干茎流量的主要因子是冠型结构、胸径、树皮特征和分枝角度。