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1.
根据山西省太原市林场红脂大小蠹的发生、发展、扩散等动态过程,探讨了G IS在红脂大小蠹综合治理中的应用。从红脂大小蠹的发生地入手,对实地进行了详细的调查研究,将野外调查资料建立了详细的数据库,初步完成了红脂大小蠹信息的数字化。建立了太原市林场电子地图,叠加了森林资源信息和红脂大小蠹分布、危害信息,对红脂大小蠹发生的区域进行了准确的定量描述,并在此基础上,利用T itanG IS软件对红脂大小蠹发生、发展规律以及与环境因子的关系进行了分析研究,为准确地确定防治面积,设计合理的防治决策,提供了依据。  相似文献   

2.
红脂大小蠹的生物学特性及在我国的发生规律   总被引:3,自引:0,他引:3  
对红脂大小蠹越冬部位及虫态,胁迫条件下的寄主、生活习性进行模拟试验,对各地红脂大小蠹的年生活史进行系统研究.结果显示,在我国红脂大小蠹各主要发生地,该害虫主要在油松伐桩、衰弱树和新死亡树的根部以大龄和老熟幼虫或少量成虫越冬.在山西、河北和河南、陕西的北部部分发生区,油松伐木树皮下也是红脂大小蠹的重要越冬场所之一 ,红脂大小蠹成虫还可以转主为害.林地火灾、割松脂作业过度和偷砍乱伐等人为不良因素干扰的林地,红脂大小蠹发生程度较重.做好林地的防火、防盗伐 ,合理的抚育是控制红脂大小蠹发生非常重要的措施.  相似文献   

3.
对外来入侵种红脂大小蠹发生和危害情况进行了研究,结果显示,阳坡危害程度要重于阴坡;不同位置以山沟路边危害最重;红脂大小蠹主要危害胸径大于30 cm的油松。通过对红脂大小蠹扬飞扩散时间的监测,发现5月上旬到6月中旬是红脂大小蠹扬飞扩散的高峰期。根据上述研究,进一步讨论了红脂大小蠹防治策略。  相似文献   

4.
分析了阳城县红脂大小蠹发生原因,介绍了红脂大小蠹形态特征及生物学特性、传播途径、为害树种和为害症状、虫情监测方法,提出了红脂大小蠹防治的营林、化学、生物、天敌等防治方法。  相似文献   

5.
红脂大小蠹伴生菌研究进展   总被引:2,自引:1,他引:1  
红脂大小蠹是我国重要的外来入侵害虫,给我国林业生产和国土生态安全带来巨大危害.包括红脂大小蠹在内的小蠹科昆虫与真菌之间存在着广泛的共生关系,伴生菌在协助昆虫建立种群、协同克服寄主抗性等方面起到重要作用.对北美原发地红脂大小蠹伴生菌的研究进行综述,以期探讨引起灾害发生的多重因素,并为灾害的控制提供思路.红脂大小蠹记载与10种长喙壳类真菌伴生,其中黑脂小蠹细帚霉、长梗细帚霉、温菲尔德细帚霉和瓦格纳长喙壳等与红脂大小蠹有着较为紧密的共生关系.对这些主要伴生菌的形态特征、系统发育关系、生活习性和致病性进行详细比较.应当警惕这些重要森林病原物对我国森林生态系统的入侵和危害.并对今后包括红脂大小蠹伴生菌在内的我国小蠹虫伴生菌的研究进行讨论.  相似文献   

6.
介绍了太原地区红脂大小蠹的生物学特性和危害特点,预测了红脂大小蠹发生的不同时期,总结了太原市国有林场红脂大小蠹防治工作中的经验和方法,提出了红脂大小蠹防治措施。  相似文献   

7.
红脂大小蠹入侵新疆的风险分析   总被引:1,自引:0,他引:1  
为有效防止红脂大小蠹(Dendroctonus valens RTB)扩散蔓延到新疆,文章根据相关文献,对红脂大小蠹的国内分布状况、潜在的危害性、寄主植物的经济重要性、传播扩散的可能性以及危险性的管理难度等几个方面进行定性和定量分析,对红脂大小蠹的危险性做出综合评价。结果表明,红脂大小蠹在新疆属于高度危险的森林有害生物。  相似文献   

8.
红脂大小蠹是为害油松林的主要害虫,爆发快,成灾面积大。介绍了南阳山林场红脂大小蠹危害情况,分析了该场油松林感染红脂大小蠹的原因,提出了综合治理红脂大小蠹的措施。  相似文献   

9.
笔者在山西省红脂大小蠹(Dendroctonus valens LeConte)发生地区做了连续调查,结果表明:油松抚育间伐林红脂大小蠹危害重于对照林;割脂与未割脂油松林红脂大小蠹危害差异显著(P=0.001),割脂油松林红脂大小蠹危害重于未割脂油松林;过火与未过火油松林红脂大小蠹危害差异显著(P=0.014),过火油松林红脂大小蠹危害重于未过火油松林;油松混交林与油松纯林红脂大小蠹危害无显著差异(P=0.828),混交林不能减轻红脂大小蠹对油松的危害;不同郁闭度下对应的平均有虫株率不完全相同(P〈0.000 1),郁闭度为0.3,0.4的林分受害最为严重;阴坡与阳坡油松林红脂大小蠹危害差异显著(P=0.000 1),阳坡油松林红脂大小蠹危害重于阴坡油松林。  相似文献   

10.
该文从害虫、寄主、环境和人类活动四个方面论述了红脂大小蠹Dendroctonus valens Lecon-te的暴发成因,建议从营林措施,监测检疫和生物防治等方面完善我国红脂大小蠹工程治理的基本思路,同时对国家级红脂大小蠹治理工程的进展情况作了简要介绍。  相似文献   

11.

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.  相似文献   

12.

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.  相似文献   

13.
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.  相似文献   

14.

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.  相似文献   

15.

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.  相似文献   

16.

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.  相似文献   

17.

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.  相似文献   

18.

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.  相似文献   

19.
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。  相似文献   

20.
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 > TithoniaEuphatorium > 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.  相似文献   

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