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印支期受特提斯板块和欧亚板块的汇集影响,沿右江褶断带＂乐业S型构造＂北旋回层的腹地,形成板塘层控微粒型金矿床。矿体呈层状、似层状,亦有分支复合现象。具有多层矿体和多种组合系分布的特点。新提出控矿岩相与浊积扇的扇中相水道前缘砂体沉积和扇末平原相的复合有关。矿石类型为石英杂砂岩,复理石韵律砂泥岩和新认识的黑色泥岩矿石。其中,硅化角砾石英杂砂岩矿石中含有＂球状石英集合体＂,黄铁矿中见有＂球粒＂疑属陨粒物质。矿石结构具有碎屑结构,变余结构,碎裂结构为主;矿石构造为层状、条带状和角砾状构造。矿石组合化学分析,具有汞、银、铜、铅、锌中～低温热液成矿特点。半定量光普分析含铜、镍、铬高,显示原矿物质组分和基性岩有关。围岩蚀变主要为硅化、黄铁矿化、褐铁矿化、高岭石化、绢云母化。主要载金矿物和黄铁矿、褐铁矿、粘土矿物有关。氧化矿体区分为风化壳残积和堆积矿体、风化沉积矿体和重力流沉积矿体,认为和冰川活动有关。从而丰富了层控微粒型金矿床的理论和深入研究＂红土型＂金矿床的内容,展示了一个完好实例。 相似文献
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马蹄莲别名慈姑花、水芋、观音莲,为天南星科马蹄莲属花卉。我国各地温室均有栽培。北方寒冷地区温室栽培,南方有露地栽培。马蹄莲是多年生草本植物。株高70~100m,地下部具肥大的深褐色肉质块茎。叶基生,叶片翠绿,心状箭形,先端锐尖,基部戟形,全缘;叶柄较粗长,上部具棱,下部呈鞘状抱茎。花梗高出叶片,具黄色圆柱状肉穗花序,直立于佛焰苞中央,上部着生雄花,下部雌花;佛焰苞常见为白色,也有粉红、黄等色,基部包旋成筒状,上部开展,先端长尖反卷,状如马蹄,故名马蹄莲。花期2~4月。果实肉质。白花马蹄莲为最常见的、栽培历史最悠久的种,巨大的佛… 相似文献
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厚朴速生丰产栽培技术 总被引：1，自引：0，他引：1
《中国林业》2007,(19)
厚朴属木兰科,木兰属,落叶乔木,高20米,树皮厚,灰色不裂,小枝粗,顶芽大,倒笔状,叶大,集生枝顶,长园状倒卵形,长23厘米~45厘米,宽9.5厘米~20厘米,钝尖,下部渐窄为楔形,花白色,芳香,长8厘米~10厘米,聚合果圆柱形,或上部较窄,长9厘米~13厘米,小果发育整齐,先端具突起的喙,花期5月,果期9月~10月。厚朴具有较高的经济价值,木材材质轻软细致,可供板料、家具、细木工等用材;也可用作煤矿壁 相似文献
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福禄考又名草荚竹桃，届花忍科福禄考属，为多年生宿根草本花卉。根茎呈半木质化，多须根。茎粗状直立，株高60～120厘米，光滑或上部有柔毛，通常不分枝。叶呈十字形对生，茎上部叶常呈三叶轮生，质薄，长椭圆状披针形至卵状被外形，先端尖，基部狭，长75～12厘米，边缘具细硬毛。塔形圆锥花序顶生，花冠粉紫色，呈高脚碟状，先端5裂，著片狭细，裂片刺毛状。福禄考性喜阳，耐寒，适宜排水良好、疏松、稍有石灰质的土壤。繁殖可用分株、压条和抒插。分株宜在早春或秋季进行。压条可在春、夏、秋季进行。打插可分为根插、茎捕及叶插。福禄考… 相似文献
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鱼腥草的栽培及开发利用 总被引：1，自引：0，他引：1
鱼腥草（Ｈｏｕｔｔｕｙｎｉａ ｃｏｒｄｅｔａ）属三白草科多年生草本植物。株高２０～６０ｃｍ，全株具鱼腥气。茎下部伏地或作地下茎状生于表土层中，白色，节上生根，茎上部直立。单叶互生，心脏形全缘，暗绿色，叶柄长１～３ｃｍ。穗状花序生于茎上端与叶对生，基部有４个白色花瓣状总苞片，花小而密集。果为蒴果。花期５～６月，果期１０～１１月。 一、适生条件 鱼腥草喜温暖，耐高温，对温度适应范围很广。在北方无霜期均可生长，冬季气温－１５℃以上可以安全越冬；喜肥沃的沙质壤土或含腐殖质丰富的土壤，在黏性或碱性土壤中能正… 相似文献
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沙地樟子松及其造林技术 总被引：1，自引：0，他引：1
樟子松也称海拉尔松,是松科松属的常绿乔木。树高可达30米,胸径70厘米,树干通直,大树树皮厚,树干下部呈灰褐色或黑褐色,深裂成不规则的鳞片块状脱落;上部树皮呈淡褐黄色,裂成薄片脱落。大枝斜展或平展,幼树树冠呈尖塔形,老树则呈现圆顶或平顶。1年生枝呈淡黄褐色,无毛。针叶二针一束,粗硬,常扭转,边缘有细齿,树脂道边生。当年生小球呆长约1厘米,下垂;球果呈卵圆形或长卯圆形,长3—6厘米,直径2—3厘米,熟时呈淡褐灰色;中部鳞片呈斜方形,多角状肥厚隆起,向后反曲,纵脊、横脊显著,鳞脐小,凸起,有易脱落的短刺。种子呈长卵圆形或倒卯圆形,长4．5--55毫米,连翅长1．1—1．5厘米。花期5—6月,球果翌年9—10月成熟。 相似文献
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圆锥绣球嫩枝扦插试验徐凤树（辽宁省林业学校１１０１０１）圆锥绣球（Ｈｇ。ｎｇ。ｐａｎｉｃｕｌａｔａ．ｃｖ．ｇｒａｎｄｉｈｏ）又称大花水亚木、细花水亚木，为虎耳草科绣球花属的落叶灌木。叶对生、有时在上部３叶轮生，椭圆形或卵状椭圆形，长６～１２Ｃｍ，有内... 相似文献
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五叶地锦的苗木培育及园林应用 总被引：3，自引：0，他引：3
五叶地锦Parthenocissusquinquefolia（Linn，）Pianch为葡萄科爬山虎属落叶攀援性木质藤本，能借助吸盘爬上墙壁或山石，枝繁叶茂，层层密布，入秋叶色红艳，格外美观，是垂直绿化中不可多得的好材料，短期内就可收到良好的绿化、美化效果。原产美国东部．故又名美国地锦、美国爬山虎，我国各地园林中早有引种栽培。1主要形态特征落叶攀援性木质藤本；幼枝带紫红色；卷须与叶对生，5—8分枝，下部的卷须长，往上逐渐变短，先端有吸盘。叶互生，具长柄，掌状复叶，具5小叶，稍革质，小叶具短柄，长圆状技计形，长4～10厘米，基部通常换形… 相似文献
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石灰岩山地水土保持林的树种选择 总被引：4，自引：0，他引：4
在石灰岩山地水土保持立地类型划分的基础上 ,参照相关研究成果 ,通过标准地调查和主要牧草的播种试验 ,以生长量和生物量为指标 ,确定了水土保持林不同立地类型适宜的树 (草 )种 相似文献
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梁孝王营建的东苑是西汉时期最具代表的私家园林。因园主的身份和地位,其也是当时唯一可以与皇家园林上林苑相媲美的诸侯苑囿。对历史辞赋、现存遗迹、文献记载和前人的研究进行综述,结果表明,东苑中运用了“苑中苑”的造园手法,土石并用、叠石造山;引水为池、师法自然,个中建设无不精巧,且初现了园林的诗画意境;其中植物种植搭配收四时之烂漫,动物种类繁多纳四海之惊奇,美学与实用并重。 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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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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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