稀有濒危植物云南金钱槭迁地保护的研究

对稀有濒危植物云南金钱槭的分布、原产地与迁地栽培地的自然条件及其迁地栽培试验结果进行了报道和分析，并首次报道了云南金钱槭的染色体数目。提出了云南金钱槭的播种育苗及迁地栽培技术。经过7年的试验，云南金钱槭巳在云南省珍稀濒危植物引种繁育中心昆明基地完成了从种子到种子的生命周期，迁地保护获得成功。     

珍稀濒危植物贺兰丁香,大叶细裂槭的引种试验

贺兰丁香、大叶细裂槭两树种是内蒙古自治区贺兰山特有植物,被定为国家三级、内蒙古二级保护的珍稀濒危植物。我园从1985年开始对以上二种珍稀濒危植物进行了迁地保护、引种试验研究。经过引种,育苗,现已获得苗木,并初步掌握了贺兰丁香、大叶细裂槭的种子处理方法,播种育苗技术,为迁地保护珍稀濒危植物积累了资料。     

稀有植物云南金钱槭的现状及保护措施

云南金钱槭(Dipteroina dyeriana)是我国特有、稀有和极危种,基于实地调查和查阅相关文献,对云南金钱槭的形态特征、地理分布、生态环境及其研究现状进行了详述,并针对云南金钱槭的生态学特性和科研提出了保护措施:建立保护区进行就地保护,进行人工培育,建立珍衡濒危植物园.     

6种槭树在武汉地区引种栽培试验初报

本文通过对武汉地区栽培的6种槭树的物候期表现,地径、树高、冠幅、耐热性、抗寒性及种子繁殖出苗率等的观测与统计,研究其在武汉地区引种栽培的适应性.结果表明：三峡槭、元宝槭、红翅械、飞蛾槭、血皮槭等5种槭树在武汉地区生长迅速,病虫害较少,种子繁殖成苗率高,适合引种栽培;金钱槭由于耐热性较差,不适合在武汉地区引种栽培.     

稀有植物云南金钱槭的扦插繁殖技术研究

对稀有植物云南金钱槭进行了扦插繁殖技术的研究。结果表明:云南金钱槭具有易生根的特点;未经处理的幼龄(3年生)云南金钱槭植株的嫩枝具备一定的生根能力。扦插繁殖技术处理的最佳组合为:以嫩枝作插穗,用浓度为100 mg/L的ABT1作浸穗处理,采用海煤土作扦插基质;其次是嫩枝200 mg/L的ABT1海煤土处理。以云南金钱槭1年生扦插苗与种子实生苗进行生长量和生物量比较,扦插苗优于种子实生苗。扦插苗的冠幅是种子苗的1.63倍,根重是2.27倍,进一步证实嫩枝扦插繁殖是云南金钱槭的一种有效可行的繁殖方法。     

五小叶槭播种育苗技术总结

五小叶槭为中国四川特有种,极度濒危。根据迁地保护计划,在甘肃省小陇山立远林场建立五小叶槭种苗繁育基地,初获成功。总结几年经验,五小叶槭播种育苗技术要点包括整地做床、种子催芽及苗期管理,揉搓去翅、覆土厚度、苗期浇水、搭盖遮阳网四要素影响出苗。     

金钱槭繁育试验研究

以种子、硬枝、嫩枝为材料采用不同生长激素、不同浓度、不同处理时间和不同栽培基质对金钱槭进行了繁育试验研究,结果表明:扦插繁殖剪口处白色分泌物遇氧变褐色,较难生根。硬枝扦插时,插条以0.01%的NAA处理20h,嫩枝扦插时,插条以0.008%的IBA处理20h,基质以蛭石+森林土为1∶1金钱槭扦插繁殖的效果较好。     

漾濞槭的研究与保护

槭树科仅有槭属和金钱槭属两个属,其中金钱槭属有云南金钱槭和金钱槭两个种,均为我国特有(Sun,2018)。槭属全球共约有129种,广泛分布于北半球温带、部分热带地区,我国该属植物约99种,其中63种为特有种(Sun,2018)。漾濞槭(A.yangbiense Y.S.Chen et Q.E.Yang)特产于我国云南省漾濞彝族自治县,其发现比较偶然。     

贺兰山大叶细裂槭拯救性保护研究

<正>2013年，贺兰山国家级自然保护区针对珍稀野生植物大叶细裂槭（Acer stenolobum Rehd.var.megalophyllum Fang et Wu）在贺兰山西坡的分布情况和稀有程度建立了就地保护基地，并进行迁地繁育试验研究。在对大叶细裂槭资源与分布调查的基础上，通过就地保护与繁育试验，对该物种的生存现状、种群结构与动态、繁育回迁等方面进行了综合研究，分析了大叶细裂槭在贺兰山西坡的生存现状，探究其濒危原因，并进行人工繁育和移栽试验，在此基础上提出了适合其在贺兰山的种群保护对策。     

南涧迁地保护127种濒危植物

云南无量山国家级自然保护区南涧管理局建成"迁地保护园",127种珍稀濒危植物得到迁地保护。云南无量山国家级自然保护区内野生植物资源丰富,是我国生物多样性特别丰富和物种分化特别明显的地区之一。迁地保护园2010年1月始     

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.     

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。     

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.     

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.