黄花倒水莲林下扦插育苗试验

在常绿阔叶树林冠下开展黄花倒水莲不同季节、不同基质、不同浓度生根剂及不同浸泡时间的扦插对比试验。结果表明:影响黄花倒水莲扦插生根的主要因子是扦插季节和扦插基质;在秋季选用林下腐殖质土,采用生根剂(NAA)200mg·kg-1浸泡3 h扦插生根率最高,生根率达92.6%。     

扶芳藤快速扩繁试验

分别采用扦插、播种和嫁接等扩繁方法,对红脉扶芳藤、宽瓣扶芳藤、紫红扶芳藤和金边扶芳藤等品种进行了快速扩繁试验,研究不同扶芳藤品种最适宜的繁殖方式和取材方法及各品种在不同繁殖方式中所需要的适宜条件和处理方法。试验结果得出:7月最适宜扦插,生根最快;红脉扶芳藤的生根能力强于宽瓣扶芳藤和紫红扶芳藤,1 a2、a生枝条强于当年枝,扦插30 d后可以进行移栽;种子经浓度为20 mg/kg的GA3处理最利于生长,根系数和株高均达到最大值。红脉扶芳藤嫁接在丝棉木上,成活率最高,达100%。     

金银花的栽培

金银花是贵重药材,能清热解毒,有较强的抗菌作用,也可作为防暑降温的饮料。它的适应性强,耐寒、耐旱,山区山坡地角均可种植,是很有用途的中药材。金银花属忍冬科半常绿缠绕灌木。它在同一株藤上开放出白如银、黄如金的花朵。采收后,黄花、白花混在一起,药效一样,所以有“二花”、“双宝花”的称号。它的藤叶也可药用。繁殖金银花有扦插、压条、分株、种籽繁殖等几种。但以扦插法简便易行,容易成活,还有早开花的特点。金银花的扦插,在春季雨水季节或秋季立秋前后为宜。要选生长健壮、无虫害的二至三年生的枝条,剪成长30-40厘米左右的插条,按…     

扶芳藤营养袋育苗试验

通过扶芳藤营养袋扦插育苗及营养袋苗移入大田的试验,探索出扶芳藤育苗的一系列技术。太原地区扦插扶芳藤的适宜时间为8月;插穗应选取木质化或半木质化的嫩枝;扶芳藤能适应太原地区的生态环境。     

两种紫葳科藤本植物扦插育苗技术研究

硬骨凌霄、紫云藤为紫葳科藤本中应用范围广、市场需求量较大的两个品种,为探索它们的扦插育苗技术,采用正交设计的试验方法对两种植物插穗规格、留叶方式、留芽数量的选取进行研究,并对正交试验的结果进行了验证,探讨了不同生根剂处理下两种植物的扦插生根情况.研究结果表明,插穗直径、插穗长度、留叶方式和留芽数量这4个因素对硬骨凌霄和紫云藤的扦插成活率有着极显著的影响.对于硬骨凌霄来说,插穗直径对其扦插成活率的影响最大,留芽数量次之,再次为留叶方式和插穗长度;对紫云藤,留芽方式是影响其扦插成活率的最关键因素,其次是插穗的直径、长度和留叶方式.生根剂的使用可以极显著提高紫葳科藤本植物的扦插成活率,选择直径0.80 cm的硬骨凌霄当年生藤条制成长8 cm、保留2个半片叶和2个芽的穗条,并用浓度为500 mg·L-1的NAA溶液处理2 h后进行扦插,扦插成活率可达83.33％;选择直径1.0 cm的紫云藤当年生藤条制成长10 cm、保留1个半片叶和2个芽的穗条,并用浓度为500 mg·L-1的NAA溶液处理2 h后进行扦插,扦插成活率也可达83.33％.本研究得出的制穗方案和生根剂的选择方案可适用于硬骨凌霄和紫云藤这两种紫葳科藤本的扦插育苗,也可为其它植物扦插育苗提供参考.     

彩叶扶芳藤扦插繁殖生根剂比较试验

采用不同生根剂用不同浓度和浸蘸方法进行彩叶扶芳藤扦插比试验。结果表明:采用"森生2号"生根剂500×10-6、穗条基部浸泡2s,生根率达87.96;采用"森生1号"生根剂500×10-6、穗条基部速蘸2s,生根率达84.26。在此基础上,组装成彩叶扶芳藤扦插繁殖配套技术。     

不同基质和生长调节剂对蒜香藤扦插繁殖的影响

蒜香藤是紫葳科蒜香藤属的优良木质藤本。为提升蒜香藤的繁育效果,采用L₉(3⁴)正交试验设计方法,通过多项反映扦插成活及根系生长的指标,探究基质、IBA浓度及NAA浓度对蒜香藤嫩枝扦插繁殖的影响。结果表明：基质对蒜香藤的生根率、总根数有极显著影响(P<0.01);IBA浓度对蒜香藤的生根率、总根数、不定根数、不定根长和生根指数有显著影响(P<0.05);NAA浓度对蒜香藤的新叶率和不定根长有显著影响(P<0.05)。隶属函数评价显示,可以从生根指数、老叶率、不定根数和总根数评价扦插效果。最适处理为插穗用100 mg·L^-1IBA+50 mg·L^-1NAA的溶液浸泡30 min,采用体积比为3∶2的河沙和泥炭土作基质。     

叶面肥和透光度对细叶青蒌藤扦插苗生长和质量的影响

采用双因素随机区组设计,研究了叶面肥和透光度对细叶青蒌藤扦插苗生长和质量影响。结果表明：叶面肥对细叶青蒌藤扦插苗的生长和质量存在着正效应,透光度对细叶青蒌藤扦插苗的生长和苗木质量有着负效应。叶面肥与透光度对细叶青蒌藤扦插苗生长量指标的新梢鲜质量、新梢长度、叶片数量、叶面积与地下根系鲜质量、主根数量有着极显著性影响;叶面肥因素作用高于透光度因素;叶面肥与透光度双因素在细叶青蒌藤扦插苗的梢鲜质量、叶片数量、叶面积性状方面存在显著性或极显著性的交互作用。     

元江县6种森林蔬菜的育苗及修剪试验

2001年3月至2003年10月,在元江县林木种苗管理工作站进行了6种森林蔬菜的育苗及修剪试验,结果表明,采用生长调节剂处理插穗后,可提高臭菜、树头菜、越南甜菜和刺五加扦插生根率,在大棚中最佳扦插时间生根率分别达80％、60％、80％、60％,吲哚丁酸好于ABTI*生根粉,大棚中扦插优于露天；其中刺五加最佳扦插时间为10月,其他3种为3月.南山藤和长蕊甜菜的种子育苗,出苗率分别为100％和92％；南山藤和长蕊甜菜最佳育苗时间分别为3月和8月.臭菜、南山藤、刺五加、树头菜和越南甜菜的最佳修剪高度分别为50 cm、50 cm、40 cm、60 cm和50 cm,与未修剪相比,分别提高了191.43％、415.63％、214.29％、336.94％和531.39％,修剪能大幅度提高森林蔬菜产量.     

三叶青不同方式繁殖栽培技术试验

在阔叶树疏林地进行了林下栽培三叶青试验,种苗采用高锰酸钾溶液、吲哚丁酸溶液不同方式浸种,不同方法栽培:其一,用容器袋育苗,扦插繁殖栽培;其二,林地下块状直接,扦插繁殖栽培;其三,整地成床,扦插繁殖栽培;经过3 a的培育,三叶青藤木生长良好。结果显示:三年生用容器袋育苗,扦插繁殖栽培生长的苗木,比林地下块状直接,扦插繁殖栽培和整地成床,扦插繁殖栽培藤长、径粗、叶面积宽大,平均均有提高。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

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.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

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.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

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.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

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.     

Modelling of adequate pretwist for obtaining straight timber

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.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

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.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

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.     

CAD与建筑设计的关系

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。