下木在森林群落中的作用

森林群落具有成层结构,一般分为乔木层、下木层、草本层、地被层。这样完整的层次,能保持生态平衡,促进体木的生长。然而,当前营造各种人工林时,忽视了这样层次的配置,只注重乔木树种的建群,不注意下木的营造。为了引起人们对下木的重视,加速林木生长,维护生态平衡,现根据我们的调查和有关资料,谈谈我区下木的种类和作用,供参考。据调查,我区下木主要有:山茶科的黄端木、柃木、油茶、茶、扬桐;豆科的大叶黄檀、胡枝子、美丽胡枝子、紧穗槐、山槐、宜昌木兰、华东木兰、锦鸡儿;蔷薇科的山桃、木梅、陷脉、石楠、石斑木;马鞭草科的大青、紫珠、华紫珠、广东紫珠、臭黄荆;樟科的     

黄花菜的栽培技术

黄花菜是一种常见的野生资源,分布范围广。由黄花干制而成的金针菜倍受人们的喜爱。它富含多种维生素、矿物质,如胡萝卜素、钙、磷、铁、蛋白质、脂肪、糖等,是人体不可缺少的营养物质;它的根、叶均可入药,养血平肝,利尿消肿,治头晕、耳鸣、心悸、腰疼、吐血、水肿、咽痛、乳痛等,是一种常用的中药材资源。尤其它的适应性很强,抗寒能力强,甚至能在海拔2000米的山顶、山坡、疏林地     

弘扬张家港精神 全力打造城乡一体的绿色港城

地处苏南沿江发达地区的张家港市,是一座年轻、充满活力的新兴港口工业城市,市域面积999平方公里,总人口95万人。近年来,在加强发展经济的同时,紧紧围绕建设最适宜人居、创业的现代化城市目标,以加强城市生态建设,创造良好的人居环境,促进城市可持续发展为中心,以创建国家园林城市为抓手,大力弘扬“团结拼搏、负重奋进、自加压力、敢于争先”的张家港精神,坚持政府组织、群众参与、部门共建、因地制宜、讲究实效的原则,高起点规划、高标准建设、高质量管理,加大力度、加大投入、城乡联动、狠抓落实,整体推进公园绿地、附属绿地、防护绿地、…     

我爱绿叶

我爱妍丽的红花,更爱金色的硕果。然而,作为一个林业工作者,我酷爱那朴实无华的绿叶。资料表明,全球有记载的高等植物约三十万种,我国约三万种。在整个植物群体中,叶子是一个庞大的家族,形态各异,种类繁多。根据叶的形态特征,一般分为鳞形、锥形、刺形、条形、针形、披针形、匙形、卵形、园形、菱形、三角形、心形、扁形等二十余种。根据叶的种类,可分为单叶、复叶。复叶又分为单身复叶、二出复叶、掌状复叶、奇数羽状复叶、偶数羽状复叶等数十种,尽管她们的形态和种类有别,但是她们的奋斗目标是一致的,就是通过自己的辛勤劳动促使植株加速生长,早日开花,尽快结果。     

湖北省长江防护林体系工程主要对策

<正> 湖北省地处长江中游,浩荡的长江江水由四川奉节经秀丽壮观的翟塘峡、巫峡奔流而下,从巴东县鳊鱼溪河口流入湖北,流经巴东、秭归、宜昌、宜都、枝江、松滋、江陵、沙市、公安、石首、监利、洪湖、嘉鱼、汉阳、武昌、武汉、新洲、黄冈、鄂洲、浠水、黄石、大冶、蕲春、阳新、广济至黄梅滨江出口,共26个县、市,境内流长1061km,占长江全长约16%,最大流量为8万m~3/s,宜昌以上江狭流急,宜昌以下逐渐平缓,世界著名的葛洲坝现代化水电枢纽工程在宜昌拦江筑坝发电,从而结束了江水白流的历史,湖北省属长江流域面     

贵州毛竹林类型与林分结构的研究

一、自然概况毛竹林是贵州竹林中面积最大,分布最广,价值最高的一种竹林。天然林分主要分布于黔北的赤水、习水的赤水河流域,其次,黔东南和黔东的黎平、天柱、锦屏、溶江、从江、江口、铜仁、松桃及雷山、剑河、印江等县亦有成片或零星分布。六十年代以来,黔中地区的贵阳、平坝、惠水、修文、遵义、仁怀、湄潭、风冈、余庆、丹寨、麻江、三都、水城等地,先后均有引造毛竹林,逐渐成林,生长良好。     

发扬红旗渠精神加快太行山造林绿化

河南省太行山北起林县,西抵济源,南濒黄河,东至京广铁路线,地跨安阳、鹤壁、焦作和新乡四个市,包括林县、鹤壁市郊区的全部,辉县、济源二市的大部,安阳县、安阳市郊区,汤阴、淇县、浚县、卫辉、修武、焦作市郊区,博爱、沁阳、孟县的一部分,共涉及15个县(市、     

绿叶的妙用

苍翠的绿叶世界,不仅洁净空气,使人心情愉快,增强人的体质,而且在创造人类文明中还作出了它应有的贡献。 各种各样的树叶,都含碳、氢、氧、氮、磷、钾、镁、钙、硅等元素,它又含有木质素、纤维素、树脂、果胶、栲胶、淀粉等有机化合物。     

笼养鸟的选择

目前,市场上适合家庭笼养的观赏鸟有100多种,它们大多小巧玲珑,羽色华丽,鸣声悦耳,能歌善舞。驯养者可根据自己的爱好、养鸟时间、条件等因素选择自己要驯养的鸟的类型。羽色艳丽羽色艳丽、体态优美的笼鸟大都娇小玲珑,招人喜欢。它的欣赏价值高,能装饰美化居室环境。这一类鸟饲养比较简单,不需调教,鸣声大多优美动听。常见的有虎皮鹦鹉、金山珍珠、相思鸟、黄鹂、红嘴蓝鹊、斑胸草雀、戴菊、牡丹鹦鹉、七彩文鸟、寿带鸟、蓝翡翠等。鸣声惊耳鸣唱婉转动听的笼养鸟,最普遍的有画眉、百灵、云雀、芙蓉、绣眼、相思鸟、红点颏、蓝点颏、黄雀、…     

怎样栽好庭院果树

庭院栽植果树,春华秋实,四季飘香,不仅可以赏心悦目,以飨口福,而且还能美化环境,净化空气,增进身心健康。利用庭院有限面积栽好果树,大有学问。一、因地制宜选择树种适于庭院栽植的果树种类很多,主要有葡萄、草莓、桃、杏、柿、李、枣、石榴、无花果、核桃、板栗、梨等。因各种果树的生物学特性不同,它们对生长要求的环境也不一样。如苹果、梨、核桃等要求土层深厚疏松,水肥条件好的沙壤土。葡萄、李、草莓对土壤要求不严,适应环境广。小枣耐盐碱,柿喜钙质,板栗则要求酸性或微酸性土壤。除土壤外,对光、温、水、肥等要求也各不相同。因此,必…     

论生态食物链在小流域治理开发中的应用

生态食物链反映了生物界互相依存、互相制约的关系。对小流域(经济沟)治理意义最大的是“粮-人”食物链、“草-畜”食物链、“地-商”食物链。增强主导食物链运行强度的“加减公式原理”,扩大粮食来源的“加加公式原理”,扩大肉、蛋、奶转化的“新金字塔原理”,调整生态食物链内外循环的“能流、物流平衡与价值流不平衡原理”,是小流域(经济沟)建设的生物学基础。为使开发治理具有活力,充满稳定和有序,必须解决“粪-土短路”问题,“粮食功能转化”不力问题,主导食物链运行强度减弱问题,土地投入产出比例失调问题,“地-商”食物链受阻问题。     

The role of extension in agroforestry development: evidence from western Kenya

The extension strategy used by the CARE International in Kenya Agroforestry Extension Project (AEP) is described. This strategy is evaluated in terms of documented changes in farmer's agroforestry practices and the importance of AEP relative to other changes in economic incentives, institutional support, and land use and tenure rules for agroforestry. The project served mainly to increase awareness of the multipurpose potential of agroforestry, expand available technical options, and strengthen local institutions. Its community-based extension approach was more suitable for local conditions than commodity-based, training-and-visit, farming systems, or media-based extension. Projects are encouraged to tailor extension design to local circumstances, use community participation to guide extension priorities, and use extensionists as catalysts and information brokers.Research undertaken while the author was a Principal Scientist at the International Council for Research in Agroforestry, Nairobi, Kenya.     

为传统名花绣球和粉团正名

为纠正植物学专著对传统名花“绣球”和“粉团”的错误考订,恢复它们的本来面目,进行了文献考证和实物比对。结果表明,《中国植物志》中的粉团Viburnumplicatum Thunb．实乃典籍中的绣球;而该书的绣球Hydrangeamacrophylla（Thunb．）Ser．,才是真正的粉团（该种曾称“八仙花”,更谬甚）。本文还对它们混淆的根源作了探讨。     

Hinweise zur Auswirkung biophysikalischer Umweltverhältnisse auf forstschädliche Insekten,untersucht insbesondere anLymantria monacha L.

Zusammenfassung Die Zentren des Schadauftretens verschiedener untersuchter forstschädlicher Insekten dürften nach zahlreichen Testungen Reizzonen umfassen, welche wieder als eine Kombination von elektrischen und magnetischen Feldern und durch diese freigelegte Metalleffekte erscheinen. Untersuchungen zur möglichen Wirksamkeit dieser Komponenten auf Vitalität und Fertilität vonLymantria monacha führten zu folgenden Ergebnissen. Es erscheint möglich, daß innerhalb von Reizzonen Sterblichkeit und Fruchtbarkeit vonLymantria monacha auch von niederfrequenten elektromagnetischen oder auch konstanten magnetischen oder elektrostatischen Feldern beeinflußt werden, die direkt oder auch über die Pflanze auf die Lebenskraft der Nonne von Wirksamkeit sind. Reizzonenbereich und Normalbereich zeigten hinsichtlich der Mortalität der Versuchstiere gegensätzliche Verhältnisse. Die Anfangsmortalität innerhalb von Reizzonen war gegenüber jener der Zuchten im Normalbereich erniedrigt, die Endmortalität vielfach erhöht. Futter aus Normalbereichen setzte in den Reizzonen, Reizzonenfutter im Normalbereich die Sterblichkeit herab und erhöhte im Normalbereich die Fruchtbarkeit. Im Normalbereich mit Normalfutter gezogene Nonnen wiesen die geringsten Zahlen an abgelegten Eiern auf, was sich besonders bei an Pflanzen eingebeutelten Tieren deutlich zeigte. Die wesentlich höhere Fruchtbarkeit von Nonnen an Pflanzen im Reizzonenbereich mag zusammen mit der hier erniedrigten Anfangsmortalität eine Erklärung zum gehäuften Auftreten vonLymantria monacha innerhalb von Reizzonen geben. Freigesetzte Metalleffekte könnten innerhalb von Reizzonen die Sterblichkeit aber auch die Fruchtbarkeit erhöhen.

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Summary The centres of damages by different forest insects, examined in this research, seem to be in zones of Earth radiations (Reizzonen), which again seem to be combinations of magnetic or electric fields and metal effects, set free by them. Examinations for possible influences of these components on vitality and fecundity ofLymantria monacha showed the following results: It seems possible, that inside of zones of earth radiations mortality and fecundity of this butterfly could be directed from magnetic or electric fields also of low frequency or electrostatic, which either directly or indirectly by the nutrients (plants) influence the vital power ofLymantria monacha. Zones of Earth radiations and normal zones showed different conditions in respect of the mortality. Mortality of larvae of first developmental stages inside of zones of Earth radiations was decreased, such of late stages increased contrary to larvae in normal zones. Plant-food of normal zones decreased the mortality of larvae in zones of Earth radiations and food of zones of Earth radiations decreased the mortality of those of normal zones and increased fecundity in the latter cases. Female butterflies reared in normal zones showed the lowest number of developed eggs, especially when reared encaged on living plants (spruce). The essentially higher fecundity ofLymantria monacha reared on plants inside of zones of Earth radiations together with the decreased mortality of first instar larvae there, may give an explantation for the increased population ofLymantria monacha inside of zones of Earth radiations. Metal effects set free inside of zones of Earth radiations could increase there the mortality but also the fecundity.

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Herrn Prof. Dipl.-Ing. Dr. ERWIN SCHIMITSCHEK zum 75. Geburtstag.

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A 1130 Wien XIII, Fasangasse 5-7, 1/8     

Changes in the physical and chemical properties of six Japanese softwoods caused by lengthy smoke-heating treatment

The effects of prolonged smoke-heating treatments on wood quality were investigated. Six Japanese softwoods were smoke-heated for 100 and 200h at a temperature of 75° ± 5°C, which was recorded inside the log. After smoke heating, wood quality, including moisture content, amounts of chemical components, relative degree of crystallinity (RDC) of cellulose, and sapwood color were examined. Moisture content decreased as a result of smoke heating, especially in sapwood, leading to a uniform distribution of moisture content within a log. Almost no difference was found in the amounts of chemical components between the control woods and the woods that were smoke-heated for 100h. However, in the wood that was smoke-heated for 200h, the amounts of holocellulose decreased, suggesting that thermal deterioration and/or degradation of hemicelluloses had occurred. We assume that the increase in RDC was caused by smoke heating with the crystallization of cellulose and/or thermal degradation of hemicelluloses. Almost no differences were found in sapwood color between the control woods and the woods that were smoke-heated for 100h. In the wood that was smoke-heated for 200h, however, L*decreased, whereas a* and b* increased. As a result, E*ab, showing the total color change, increased, resulting in a deeper color. These results suggest that thermal degradation of hemicelluloses was caused by smoke heating for over 100h. Therefore, smoke heating of softwood logs using a commercial-scale kiln should not exceed 100h.     

Stock quality and field performance of Pinus patula seedlings produced under two nursery growing regimes during seven different nursery production periods

Two types of containerized P. patula seedlings, referred to as hard and soft seedlings, were raised by droughting and different fertilizer applications. Hard seedlings were raised by applying half the water and a quarter of the fertilizer (0.01 g per seedling 21%N:7.1%P:14.2%K) applied to the soft seedlings. At the end of the nursery cultural treatments the two types of seedlings were morphologically distinct. Hard seedlings had lower heights, height to root collar diameter ratios and seedling dry masses than soft seedlings, but mortality was similar for both seedling types when planted during seven different production periods within the planting season on three sites which differed climatically and geologically. Correlations between mortality and height to root collar diameter ratio (r = 0.76), root to shoot ratio (r = 0.83) and root growth potential (r = --0.69) were obtained indicating that grading of seedlings on these parameters may improve survival. However, it was evident that survival could be significantly improved by identifying the best time of year and conditions for planting, as well as improving stock quality.     

Paraiso (Melia azedarach var. “Gigante”) woodlots: an agroforestry alternative for the small farmer in Paraguay

This paper describes the salient aspects and analyses the potential of the Paraiso Woodlot System, which is becoming popular as an agroforestry alternative to land use in the degraded acid sandy soils of the humid sub-tropical Guayaybi area of Paraguay. The system consists of a combination of paraiso (Melia azedarach var gigante) with other trees, especially Leucaena leucocephala, and annual crops.The fast growth habit, deep root system, addition of large quantities of organic matter through leaf and litter fall, compatibility with agricultural crops, high value of the sawlogs and production of substantial quantities of poles and firewood make paraiso an excellent species for agroforestry combination. Preliminary results of the trials indicate that the woodlots are successful and with increasing efforts of the extension agencies, they are being accepted as a viable alternative to traditional agricultural systems.Besides discussing the potential of these woodlots based on initial results, the paper identifies the constraints of the system and highlights the priority research areas.     

Dimensional instability of cement bonded particleboard: Modelling CBPB as a composite of two materials

Previous papers have quantitatively indicated that the total movement of cement bonded particleboard (CBPB) is equal to the sum of the movement of its components. This paper examined the efficacy of the law of mixtures when applied to the movement of a wood-cement composite under internal swelling or shrinkage stresses. Abundant data generated in companion papers were first manipulated to develop the universal formulae for predicting the movement of components. In conjunction with previous numerical results from image analysis of the structure of CBPB, and the orientated elasticity and stress algorithms, the models for theoretically predicting mass and dimensional changes of CBPB were derived. Validation studies were conducted and these demonstrated an excellent agreement of the theoretical predictions with experimental data for both mass and dimensional changes of CBPB due to internal swelling or shrinkage stresses during adsorption and desorption. The success also implied that CBPB can be treated as a composite and its properties can be well derived by the law of mixtures even though CBPB is an unusual type of composite having a very high volume fraction of wood chips, but a very high mass fraction of cement paste.Notation E_RT Mean transverse modulus of elasticity of wood - E_L Longitudinal modulus of elasticity of wood - E_p Modulus of elasticity of cement paste - E_wa Modulus of elasticity of embedded wood chips at angle - E Modulus of elasticity of wood chips at direction - E Modulus of elasticity of wood chips at direction - G_LRT Mean transverse shear modulus of wood - L(T)_cp Length/width (thickness) change of CBPB at angle - L(T)_p Length (thickness) change of cement paste - m_pf Mass fraction of cement paste in unit mass of CBPB - m_wf Mass fraction of wood chips in unit mass of CBPB - M_cpj Mass change of CBPB at the various conditions tested - M_pj Mass change of cement paste at corresponding conditions - M_wj Mass change of wood chips at corresponding conditions - M(L; T)_w/P Mass, length or thickness changes of wood chips or cement paste at various conditions - t Duration of exposure - _LRT Mean transverse Poissons ratio of wood - V_pf Volume fraction of cement paste in unit mass of CBPB - V_wf Volume fraction of wood chip in unit mass of CBPB - _cp Density of CBPB - _k Density of wood chip or cement paste - _cp Overall stresses of CBPB at angle - _L Stress in the longitudinal direction of wood - _RT Mean stress in the transverse direction of wood - _p Stress of cement paste - _w Stress of the wood chips at angle - Stress of the wood chips at direction - Stress of the chip at direction - _cp Strain in CBPB - _p Strain of cement paste - _WL Strain in the length of wood chips - _WT Strain in the thickness of wood chips - _w Strain in wood chips - Angle between the longitudinal direction of wood chips and surfaces or edges of CBPB - Angle between wood chips and edges (length direction) of CBPB - Angle between wood chip and vertical coordinate - A, B, C Coefficients related to the feature of materials and exposure conditions The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support.     

仁用杏良种选择研究

1997-2003年,在陕北榆林沙盖黄土区和黄土丘陵区,通过对引进的仁用杏品种设点观测,和对物候期、生长量、产量、出仁率、杏仁品质及抗病虫、抗霜冻等性能进行调查,尤其从抗冻性能上对不同仁用杏品种进行评述．提出了适于陕北地区栽培的仁用杏抗霜冻品种为“优一”。“一窝蜂”的抗冻性能优于“龙王帽”和“白玉扁”,“龙王帽”和“白玉扁”的抗冻能力较差。     

Effect of cutting position on rooting and shoot growth of two poplar clones

One-year-old shoots from stooling beds of Populus × deltoides Walker and Populus jackii Northwest were collected in late fall to determine the effect of cutting position on rooting and growth of hardwood poplar cuttings. Cuttings with a minimum diameter of 9.0 mm were obtained from basal, middle and distal locations on the poplar shoot. Rooting and shoot growth were assessed in the greenhouse and under field conditions. Walker poplar cuttings collected from basal portions of the shoot and planted in the field had 87.6% rooting and 103.8 cm growth compared to 78.8% and 103.4 cm and 67.6% and 88.8 cm for middle and distal locations respectively. For Northwest rooting and growth under field conditions was 84.4% and 94.7 cm for basal, 78.4% and 90.5 cm for mid and 64.4% and 84.3 cm for distal locations. Rooting in the greenhouse was superior to the field. Walker cuttings had fewer roots and buds per cutting than Northwest, however, growth of Walker in the field was superior.