闽楠大树移栽技术

闽楠Phoebe bournei属樟科Lauraceae楠属,为亚热带常绿阔叶树种,是中国特有的国家二级珍稀濒危植物.分布于江西、福建、浙江、广东、广西以及湖南、湖北、贵州等省.适宜于温暖、湿度大,风小、雨水丰沛的气候条件和土层深厚、肥沃、湿润、排水良好的土壤,能耐间隙性的短期水浸.其属深根树种,根系较发达,根部有较强的萌生力,幼年阶段1年可形成3次顶芽,抽3次新梢,喜湿耐荫.     

Resources of Cinnamomum camphora and Its Utilization

樟树为樟科樟属常绿乔木,为国家Ⅱ级保护树种,主要分布在中国(包括台湾)南部各省,越南、日本等地亦有分布.在中国南方,樟树是著名的多用途乡土珍贵用材和经济树种,一直被人们所重视.文章从樟树的自然分布、生态习性、木材性质、用途、生长潜能、生产力与碳汇能力、遗传改良进展、当前开发利用中存在的问题与未来展望等方面,进行了综合的论述.     

优良风景观赏树种——金钱松

金钱松是松科金钱松属乔木树种，系东亚孓遗植物，为我国特有的单种属植物。我国已列入国家二级重点保护树种名录。金钱松主要分布于江苏南部、浙江、江西庐山、安徽南部、福建北部、湖南、湖北等地，残留极少天然单株和小片分布，在海拔800～1600m地带散生于针叶树、阔叶树林中，安徽黄山有散生分布。     

杜仲引种育苗初获成功

杜仲是落叶乔木,分布在北纬22～42°,东经100～120°,垂直分布在海拔300～1300m,能耐-20℃低温,以贵州、四川、湖北及陕西南部较多。杜仲属阳性树种,喜温和湿润气候及肥沃疏松的微酸、中性或微碱性土壤。     

刀把木材质和用途的初步研究

刀把木(Cinnamomum pittos poroides)又名大果樟或桂皮树,是樟科、樟属的一种野生木本油料植物。乔木,高达25米,胸径达50厘米。主要分布楚雄州的大姚、姚安、牟定、南华、双柏,大理州的宾川、祥云、南涧等县及滇东南文山州的屏边、西畴、马关、麻栗坡等县海拔1800—2500米的中山湿性常绿阔叶林内。四川南部的会理、会东、米易、宁南等县亦有分布。通过分析,果实含油脂高达56.78％,而且     

木荷防火林带更新技术

木荷属茶科(Theaceae),学名:Schima Superba Gardn et Champ。它是我国珍贵的用材树种,又是最好的防火树种。在我国南方分布很广,包括江苏苏州地区、安徽南部、台湾、福建、江西、浙江、湖北、湖南、四川、云南、贵州、广东、广西等省(区)。对土壤适应性很强,凡酸性土壤,如红壤、红黄壤、黄壤、黄棕壤均能生长。它能与马尾松、杉木、樟科、壳斗科等常绿树种混生。迹地、荒山均能天然下种或萌芽更新。福建省尤溪县1959年就开始在山脊上营造木荷,做为防火林带。据统计,全县各类     

樟树资源及其开发利用

樟树为樟科樟属常绿乔木,为国家Ⅱ级保护树种,主要分布在中国（包括台湾）南部各省,越南、日本等地亦有分布。在中国南方,樟树是著名的多用途乡土珍贵用材和经济树种,一直被人们所重视。文章从樟树的自然分布、生态习性、木材性质、用途、生长潜能、生产力与碳汇能力、遗传改良进展、当前开发利用中存在的问题与未来展望等方面,进行了综合的论述。     

珙(王同)的染色体数目简报

珙(王同)科珙(王同)(Davidia involucrataBaill.),又名鸽子树,自然分布于我国湖北西部、四川西部和南部、贵州东北部、湖南西部及云南中部等中亚热带山地海拔1200—2500米的常绿、落叶、阔叶混交林中,是距今约6千万年前起源于新生代初期第三纪古热带植物区系的孑遗种,为我国特有的珍贵树种,已被国家列为一级重点保护植物。每年4—5月珙(王同)开花期间,在紫红色的顶生头状花序下部,着生有两片巨大的白色苞片,形似展翅高飞的白鸽,一树     

东莞樟科林木资源分布特征

采用2 km×2 km的UTM网格取样法及相邻样方法对东莞市樟科林木资源进行调查,统计每个样地乔木树种植株数量、胸高断面积以及物种多样性指数,分析樟科林木资源的分布特征和规律,结果表明:(1)在东莞市的天然森林里,樟科林木以润楠属、樟属和木姜子属为主,常见树种多为阳生性先锋树种,如豺皮樟(Litsea rotundifolia)、山苍子(L. cubeba)、潺槁树(L. glutinosa)等,以及中性长寿树种黄樟(Cinnamomum porrectum)和浙江润楠(Machilus chekiangensis),其他树种均为零星分布.浙江润楠、黄樟、山苍子、豺皮樟等种类海拔区间分布较宽,各样地几乎都有分布,而潺槁树明显更多地集中分布在中低海拔的山地中;(2)属国家重点保护野生植物的仅有樟树(C. camphora )1种,属我国栽培的常绿硬木类珍贵树种有黄樟、浙江润楠和樟树3种;(3)樟科林木种数与群落所有林木植株数量、群落丰富度及香侬韦纳多样性指数均存在正相关关系;(4)樟科林木的植株密度与海拔显著相关,高海拔森林群落中明显比低海拔地区的大;(5)樟科林木胸高断面积与海拔、樟科林木植株数量及优势种种类等相关性显著;(6)浙江润楠具有集群分布、且树木径级较大等特点,且其海拔分布区间较宽,其木材资源在东莞市天然森林里占有重要的地位.     

银鹊树的生物学特性及应用前景

银鹊树,属省沽油科银鹊树属树种,为我国特产,被列为国家三级保护珍稀植物.天然分布于我国西南及中部亚热带山区,安徽、浙江、江西、广东、贵州、湖南、湖北、四川、云南等省均有分布.安徽大别山和皖南黄山及清凉峰自然保护区垂直分布于海拔300～800m的山谷坡地.     

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.