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杨十斑吉丁入侵新疆的风险分析 总被引：1，自引：0，他引：1
杨十斑吉丁是多种杨树、防护林和园林绿化等树种的重要害虫,研究杨十斑吉丁入侵新疆的风险分析,为新疆林业上的杨十斑吉丁危险性进一步研究提供重要参考和依据。通过定性因素和定量指标体系相结合的方法对杨十斑吉丁蔓延的风险进行评估。结果表明,杨十斑吉丁是新疆林业的重要有害生物,该虫的风险值为2.11,属于高度危险性林业有害生物,对新疆林业生态建设和林业生产发展都构成了很大的威胁。提出了降低杨十斑吉丁风险的管理措施,为控制该虫扩散蔓延,开展综合治理技术及系统控制提供了科学依据。 相似文献
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总结分析2023年全国主要林业有害生物发生情况,研判2024年发生趋势。2023年全国主要林业有害生物持续高发态势趋缓,但仍属偏重发生、局部成灾,全年发生面积1 092.30万hm2,同比下降7.98%;松材线虫Bursaphelenchus xylophilus等重大外来有害生物扩散势头减缓,但危害程度依然严重;林业鼠(兔)害、钻蛀类害虫、松树病害等在“三北”、华南、西南等多地危害严重;食叶害虫、经济林病虫等其他本土常发性林业有害生物整体平稳发生、局部偏重。预测2024年全国主要林业有害生物整体仍偏重发生、局地成灾,全年发生面积1 150万hm2;松材线虫病疫情扩散势头进一步减缓,但仍呈点状散发态势,控增量、消存量压力大;美国白蛾Hyphantria cunea疫情扩散势头减缓,整体轻度发生,黄淮下游流域局部地区可能偏重危害;林业鼠(兔)害、杨树蛀干害虫和松树病害在“三北”防护林和天然林部分区域有偏重成灾风险;松树钻蛀类害虫在东北、华南、西南常发区多地将延续危害偏重态势;其他本土常发性林业有害生物在全国大部分发生区整体将轻度发生,局部地区可能偏重发生。针对当前形... 相似文献
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柳尖胸沫蝉(Aphrophora costalis Matsumura)是危害柳树、杨树、果园、各种果树和苗圃和四旁绿化树种的重要害虫,近几年柳尖胸沫蝉对阿勒泰地区的杨柳科树种危害日益严重.对柳尖胸沫蝉进行初步生物学研究表明,在阿勒泰林区该虫1年发生1代,幼虫主要危害杨柳科树种的新生叶片,叶柄、嫩枝皮层,尤其若虫对柳树人工幼林、苗木危害严重,造成柳树死亡.查清了该类害虫的危害时期及危害程度,对其幼虫期采取综合性防治措施,开展环保性生物防治技术研究,为阿勒泰林业生态建设健康发展提供参考. 相似文献
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辽宁省林业有害生物发生危害分析 总被引：1，自引：0，他引：1
《辽宁林业科技》2017,(1)
通过对辽宁省林业有害生物种类及发生情况的全面调查,分析了林业有害生物种类组成情况,在不同起源林分、不同区域的种类分布和发生危害情况。结果表明:辽宁省林业有害生物种类以害虫为主,占总有害生物的74.44%。害虫中鳞翅目最多,占比达到近一半;其次是鞘翅目占比达到1/3。在区域分布上辽东山区林业有害生物种类最多,其次是辽南沿海地区及辽中平原区,辽西丘陵区和辽北低山丘陵地区相对较少。辽东和辽西区域林业有害生物发生面积最大,分别为251 500 hm~2、242 413 hm~2,分别占全省发生面积的35.46%、34.18%,总计占比达到近70%;而辽南、辽北区域林业有害生物发生面积相对小得多。林业有害生物在人工林中占有绝对优势,发生面积达到498 027 hm~2,占全省林业有害生物发生面积的70.23%;而天然林林业有害生物发生面积要少一半,为211 047 hm~2,占全省林业有害生物发生面积的29.76%。建议在辽东山区天然次生林区域采取生态、生物为主的防控措施,辅以药剂防治,实现在防治林业有害生物的同时,最大限度地减少对生态环境的破坏。 相似文献
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总结分析2019年全国主要林业有害生物发生情况,依据林业有害生物发生规律、林间基数、寄主分布及气象条件等因素,研判2020年发生趋势,提出相应对策建议。2019年全国主要林业有害生物偏重发生,发生面积1 236.77万hm^2,呈现出松材线虫病等重大检疫性有害生物疫情扩散迅猛、危害严重,落叶松毛虫大面积暴发等突发事件多、局部成灾,松树钻蛀类害虫危害加剧,其他常发性林业有害生物整体轻度危害等特点。预计2020年全国主要林业有害生物仍将偏重发生,预测全年发生面积1 266万hm^2左右,松材线虫病等重大危险性林业有害生物在全国扩散蔓延势头不减,防控形势十分严峻;松树蛀干害虫仍将偏重发生,危害扩大;林业鼠(兔)害、杨树食叶害虫、林木病害等常发性林业有害生物平稳发生,局部地区偏重成灾。林业有害生物防治工作需要各级党委政府、林业主管部门和全社会高度重视,采取切实有效措施,努力遏制高发、频发、多发态势,维护国家生物安全、生态安全和人民群众生命财产安全。 相似文献
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粤北林业有害生物调查 总被引：1，自引：0，他引：1
为了解粤北地区林业有害生物发生动态以及危害状况,采用踏查和标准地调查相结合的方法,主要在粤北四县对林业有害生物的发生危害现状进行了调查,基本摸清了粤北林业有害生物常发种类、寄主植物、分布地点、发生面积、危害严重程度等,并对主要有害生物的未来发生风险进行了评估。通过普查,粤北地区常见的病虫及外来有害生物达112种,其中病害51种,昆虫57种,外来有害生物4种。其中危害范围大,程度较为严重的有15种,如松材线虫病、松墨天牛、马尾松毛虫,马尾松赤枯病、杉木枯梢病等。其中在仁化县红山镇新竹村发现毛竹枯梢病,大面积的毛竹已经完全枯死,翁源县全县毛竹枯梢病发生较严重,病害率高达90%以上。主要经济树种杉木受病虫危害较为明显,全县均表现出不同程度的受害症状。乐昌市今年首次发现松材线虫病。通过调查,为今后制定合理的粤北林业有害生物治理方案,更加有效地控制林业有害生物提供科学依据。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
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
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
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
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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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):118-130
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. 相似文献
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Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
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. 相似文献
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《Wood material science & engineering》2013,8(2):76-84
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
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
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
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
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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
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Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
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