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1.
太宽河自然保护区位于山西中条山中段,经调查该保护区有维管植物119科464属887种.种子植物为112科455属870种,其中10属以上的科有10个,共215属411种;仅含1属的科有48科,其中1属1种的为29科.该区分布有较多的只含1种植物的属,有277属.科分布类型主要是世界广布(36.61%)、泛热带分布(29.48%)和北温带分布(21.43%).属种分布类型中温带成分占优势,各类温带分布属高达262属,占该区总属数的57.58%;各类温带分布种(不包括中国特有种)有482个,占该区总种数的55.4%.植物区系特征表现为种类丰富、起源古老、温带特性和过渡性明显及分布有较多的珍稀濒危植物. 相似文献
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2000—2008年采用系统调查和资料收集相结合的方法对云南省楚雄市紫溪山省级自然保护区的维管植物区系进行了调查,共统计到维管植物153科、429属、723种(包括变种、亚种和多年栽培种)。维管植物分布区类型组成是温带起源的科占总非世界分布科数的44.14%,温带分布属占总非世界分布属数的35.00%,其中,以北温带分布属最多,占总非世界分布属数的26.84%,其次是热带、亚热带分布科占总非世界分布科数的41.44%,热带分布属占总非世界分布属数的25.53%。说明紫溪山植物区系不仅具有温带性质,而且具有热带性质,是二者兼容的地区,属于中国-喜马拉雅森林植物区、云南高原地区、滇中植物省,为古热带植物区系与泛北极植物区系的结合。分布区类型的组成也表明此区系古特有种丰富。 相似文献
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新疆甘家湖自然保护区种子植物共有42科137属233种,植物区系组成中最大科是藜科(24属69种),该科也正是新疆盐生植物区系最大的科;本研究区盐生植物有69属99种,占总属及种数的50.4%、42.5%;除世界分布科外,温带分布科和热带至温带分布科占第一位,各均含10种;属的地理成分中以地中海区、西亚至中亚分布型(含变型)占优势, 有45属,占总属数的39.8%;种的区系以温带成分(53.1%)和古地中海成分(42.4%)占绝对优势,中亚分布型(27.0%)、温带亚洲分布型(25.7%)、旧世界温带分布型(21.6%)比重明显大。区系基本特征表现为:优势科现象明显,单种属和少种属占据比率很高;地理成分优势性显著,来源较广泛,有一定古老成分,特有程度极低,具极为明显的盐生性质和温带干旱区荒漠性质;区系中包含国家级和省级重点保护珍稀濒危植物11种和被认为"新疆可能已消失的物种"中的3个种,都具有极其重要的保护价值。 相似文献
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《湖南林业科技》2018,(6)
通过对福建省三明仙人谷国家森林公园植物资源详细调查和大量标本采集、鉴定的基础上,对其种子植物的科、属组成,分布区类型,区系特征等进行了统计和分析。结果表明:本森林公园种子植物类型丰富,共有种子植物106科,283属,468种;优势科、属比较明显,10种以上的优势科所含的种数占本森林公园种子植物总数的47. 22%,含5种及以上的属所含的种数占本森林公园种子植物总数的14. 32%;地理成分复杂,本森林公园种子植物属的分布区类型达13种之多;区系具明显热带性质,同时也包含较多的温带成分,热带分布63科,占71. 59%,热带分布178属,占63. 12%,同时,温带分布24科,占27. 27%,温带分布68属,占24. 11%。 相似文献
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《西部林业科学》2017,(2)
通过实地调查和引种培育方法,对地处云南省西南部的无量山国家级自然保护区野生果树资源特征进行了分析,结果表明,无量山野生果树共计有245种,分属于47科95属,其中裸子植物3科4属8种,被子植物44科91属236种。其野生果树的植物区系包括14个分布类型,其中世界分布的有8科,占总科数的16.67%;热带、亚热带分布的有27科,占本区野生果树总科数的56.25%;温带分布有13科,占总科数27.08%。果实类型包括核果、仁果、浆果、坚果和柑果等5种,以浆果为主。无量山野生果树资源丰富,与热带亚洲植物区系和泛热带植物区系有密切的关系,体现了亚热带的典型区系特征。生活型多样,以高位芽植物占优势。通过相似性系数的比较,该区野生果树植物在科、属、种水平上与哀牢山的关系最密切。 相似文献
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据初步调查,金汤孔玉自然保护区的种子植物计有381种,分属于68个科201个属。科可划为12个分布型或变型,属可划为23个分布型或变型。对其科、属的区系分析结果表明,该保护区的种子植物属泛热带和温带性质的科共占74.07%,热带性质的属占总属数的32.59%,北温带分布型的属占总属数34.25%,其他温带性质的属占总属数的15.47%。本自然保护区的植物与东亚-北美间断、东亚和墨西哥间断、地中海区、西亚-中亚、中亚-喜马拉雅、东亚、中国-喜马拉雅、中国-日本等分布区联系紧密。保护区有5种地域性特有种。其植物区系特点是以温带性质为主、兼有热带性质,并具有起源的古老性、成分的复杂性和地理联系的广泛性。 相似文献
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《浙江林业科技》2017,(3)
2013-2015年,对景宁县望东垟高山湿地自然保护区和大仰湖湿地群自然保护区进行了植物资源调查,结合历史资料统计分析了两个保护区种子植物区系。结果表明,两个保护区共有种子植物153科725属1 692种,其中野生种子植物141科644属1 529种。从科级水平看,以寡种科最多,共70科,占总科数的49.6%,其次是单种科29科,占20.6%,大种科最少,仅6个,占总科数的4.3%。从属级水平看,寡种属、单种属极为丰富,分别有243属和353属,占总属数的37.70%和54.8%。科的分布区类型,热带性地理成分63科(不含广布),占总科数的67.0%,温带成分31科,占总科数的33%,说明科的地理成分具有较强的热带性质。属的分布区类型,热带分布类型256属,占总属数(不包括世界分布属)的43.6%,温带分布类型319属,占总属数的54.3%,说明具有温带和亚热带性质。调查显示两个保护区植物多样性丰富,区系起源古老,孑遗植物多,特有属种多,区系成分复杂多样,具有较明显的过渡现象。 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
18.
《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