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加强党的建设为樟子松林区改革和振兴服务中共红花尔基林业局党委书记额尔敦红花尔基林业局地处呼伦贝尔草原南部的森林草原过渡带上，是典型的次生林经营局。施业区内经营着全国最大的稀有珍贵沙地树种樟子松，是国家重点种子林基地。在当前深化改革的大潮中，红花尔基林... 相似文献
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红花尔基樟子松林灭火战法初探 总被引：1，自引：0，他引：1
红花尔基樟子松林带地处内蒙古大兴安岭西坡中段的呼伦贝尔盟红花尔基林业局，总面积２９．１万公顷，占林业局总经营面积的４８．７％。主体为西南、东北走向，长约１２０公里，宽约３０公里，呈带状分布，是我国唯一、亚洲最大、集中连片的沙地樟子松特种用途林，是自治区级自然保护区。樟子松具有耐寒、耐旱、耐脊的生物学特点，被国家确定为定向、定点经营沙地天然樟子松种子的母树林生产基地，也是“三北”防护林工程建设的重要组成部分。 一、樟子松林带特点和对火灾的影响 （一）地形、植被、气候特点 红花尔基樟子松林带覆盖主体以… 相似文献
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红花尔基沙地樟子松造林技术本栏编辑程月华白景阳红花尔基林业局位于呼伦贝尔草原沙地与大兴安岭山地接壤地带，境内主要为松林沙土、生草沙土、黑钙土、灰色森林上，年均降水量３４４～３７５毫米，年均气温－１．５℃，适宜樟子松林木生长。为了扩大樟子松林面积，增加... 相似文献
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樟子松的故乡─—红花尔基，是我国最大的沙地樟子松林区，是我国天然樟子松的“基因库‘’和“能源库”。 樟子松为欧洲赤松的变种，是我国北方特有的国家二级珍贵树种。它具有抗严寒、耐干旱、适应性强、生长快等优良生物学特性，是三北地区防风固沙、园林绿化的优良树种之一。 近年来，由于红花尔基樟子松林区所处的特殊地理位置、独特的森林景观和拥有的珍贵树种，已越来越为世人所瞩目。国内外的众多专家和学者都纷纷来此观光旅游和科学考察。田纪云、姜春云、温家宝等党和国家领导人也先后来此视察指导工作，并指示一定要保护、管理、… 相似文献
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不同强度林火干扰对红花尔基樟子松天然林更新的影响 总被引：1，自引：0，他引：1
在依据火烧迹地林木烧伤程度确定林火强度基础上,对内蒙古红花尔基樟子松林国家级自然保护区不同林火强度下的幼苗更新状况进行调查和分析,以期探明自然条件下林火干扰对樟子松天然林更新的影响,为今后开展林火促进更新方面提供科学依据。结果表明:不同火烧强度下更新树种均为樟子松;樟子松天然更新株数介于2 500~6 500株·hm-2,平均值为4 542株·hm-2;樟子松天然更新频度介于50%~100%,平均值为89%;表明林火能够促进樟子松天然更新。随着火烧程度增加,樟子松天然更新株数和频度显著降低,轻度和中度火烧更有利于促进樟子松天然更新,而重度和极重度火烧下樟子松仍能天然更新。 相似文献
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内蒙古红花尔基樟子松林国家级自然保护区"5.16"火灾后的森林天然更新调查结果表明,保护区的樟子松具有极强的自我更新能力。建议保护区火烧迹地上的植被恢复方式应以天然更新为主,在成活的下种母树不足的地段,采取适度的人工干预。 相似文献
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樟子松耐寒、耐旱、耐贫瘠、抗性强、生长快,天然更新良好,育苗和人工造林比较容易成功,是半干旱地区荒山造林,防风固沙和庭院绿化的优良树种。红花尔基林业局樟子松林带是我国最大的 相似文献
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樟子松林在我国境内的分布很局限。沙地樟子松林仅集中分布在呼伦贝尔高原东部,海拉尔河中游及支流伊敏河、辉河流域和哈拉哈河上游一带的固定沙丘上。其中面积最大的一片位于红花尔基以南,目前已由建国初的13.2万亩增加到180万亩,是国家重点抚育保护对象和采种基地。由于樟子松属极易燃植物,火对沙地樟子松林的威胁受到了有关部门的高度重视。本文依据野外考察资料,试就火烧对红花尔基一带沙地樟子松林的影响做初步探讨。 相似文献
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被誉为“樟子松故乡”的红花尔基,樟子松林面积广阔,四季常青,优良的樟子松种子源源不断地运往三北广大地区,成了全国重要的樟子松种子基地。建国40年来,红花尔基林业职工为建设种子基地走出一条鲜为人知的道路。在解放初期,红花尔基一带的原始樟子松林被日俄掠夺殆 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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《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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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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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
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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