世界紫檀属树种及其在我国的引种前景

蝶形花科紫檀属树种大多为珍贵用材树种,在全世界各热带地区均有分布。其木材材质优良,属红木之列,为世界名材。文章系统介绍了世界紫檀属树种的种类、天然分布、经济价值以及造林和经营技术,并展望了紫檀属树种在我国的引种和发展前景,旨在为紫檀属树种在我国的引种、栽培提供信息和依据。     

古巴紫檀的开发利用和发展前景

古巴紫檀是一个制作家具的优良树种。它耐干旱和0℃以上低温，生长较为迅速，17年生人工林年均树高、胸径生长量分别在1m和lcm以上。与紫檀属其他树种相比，它具有两个显著特点：①树干通直，分叉少，枝下高达10m；②心材形成早，7年即开始形成心材，而且心材比例大，20年生林木的心才比例达70％。它适合在我国北回归线以南地区推广栽培。由于我国古巴紫檀的遗传资源极为有限，进行二次引种，开展杂交育种研究是扩大其遗传基础，推动其快速发展的必由之路。     

热带速生珍贵紫檀属树种

系统介绍世界范围内紫檀属树种的种娄、分布、生长特性,人工林营造术材性质与加工利用．非木质林产品利用等。蝶形花科紫檀属分布于世界热带地区多为速生珍贵树种其材质优良．属红大之列,为世界名材。我国已有部分栽培,并对引种前景进行评述。     

紫檀属树种实生苗培育技术的研究

对早期引种并已正常开花结实的印度紫檀、檀香紫檀、马拉巴紫檀和古巴紫檀的实生苗培育技术进行了研究 ,结果表明 :去翅荚果袋装贮于室内可达 1年以上而不影响发芽率 ;用 6 0℃或 80℃温水浸泡荚果2 4h可明显提高马拉巴紫檀、古巴紫檀荚果的发芽率 ,分别由 1 1 .0 %和 6 .0 %提高到 31 .7%和 4 8.0 % ;但这种方法不利于印度紫檀、檀香紫檀荚果的萌发 ,其发芽率反而下降 ;30～ 35℃气温有利于荚果发芽和苗木生长 ;高 30cm以上的健壮苗木可以短时间忍耐 0℃低温 ,4个树种苗期耐低温能力依次为檀香紫檀 >印度紫檀 >马拉巴紫檀 >古巴紫檀。研究结果为紫檀属树种在我国的扩大栽培提供了技术储备     

湖北省湿地松栽培区划

湖北省湿地松栽培区划许业洲，周全国（湖北省林业科学研究院）前言湿地松原产美国东南部，属南方松类，生长迅速，干形通直，材质良好，是优良的用材和采脂树种。湿地松也是我国南亚热带至北亚热带引种较早、推广面积很广的树种之一。我省自１９４７年引种以来，由开始的...     

班克松在大兴安岭南部地区引种研究

班克松是优良的用材和绿化树种，原产北美洲。我国北京、河南和黑龙江伊春已引种栽培成功。松岭林业局１９８５年将其引种于大安岭南部地区，经１１年的研究，人工林在当地自然条件下已完成了生长、发育和结实过程，林木树干通直，长势良好。该引种点是目前班克公在我国最北部的引种点，为丰富当地树种资源和进一步大面积引种提供了依据。     

班克松大兴安岭南部地区引种研究

班克松是优良的用材和绿化树种，原产北美洲，我国北京，河南和黑龙江伊春已引种栽培成功，松岭林业局１９８５年将其引种于大安岭南部地区，经１１年的研究，人工林在当地自然条件下已完成了生长，发育和结实过程，林木树干通直，长势良好，该引种点是目前班克公在我国最北部的引种点，为丰富当地树种资源和进一步大面积引种提供了依据。     

黄金风铃木、鸡冠刺桐和雄黄豆的引种与栽培

黄金风铃木、鸡冠刺桐和雄黄豆是广州及珠三角地区近年来引进的同林绿化树种，本文介绍其形态特征、生物学特性及引种栽培情况。引种栽培结果表明，三个树种的生长性状良好，适于在华南地区种植，是庭园景观树种和道路遮荫的好树种。     

应用聚类分析划分朝鲜黄杨引种区

1983年,我们由辽宁引种朝鲜黄杨,经几年试验,在忻州市可露地安全越冬,生长良好,并于1985年开始结实,种子发芽率达70％以上。一、朝鲜黄杨在忻州市引种分析朝鲜黄杨(Buxus mierophylla var.koreana Nakai)属黄杨科,为常绿阔叶灌木或小乔木。在忻州市4月初叶色变绿,4月中旬进入盛花期,花清香。枝叶繁茂,耐修剪,是栽培绿篱的优良树种。原产日本、朝鲜,30年代引入我国辽宁省,在锦州、鞍山、沈阳等平原城镇广泛栽培。栽培区属温     

木兰科植物引种试验初报

九江珍稀濒危植物种质资源库内木兰园，从1983年开始引种木兰科6属53种植物。经过5年多引种驯化栽培，生长理想或比较好的有46种，占引种总数的90％。本文介绍了各引进树种在新的环境条件下的生长发育表现，包括适应性、越冬性、越夏性，从而初步筛选出适宜于九江引种栽培的树种。     

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.     

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.     

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.     

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。