《桉树科技》投稿须知

《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊（半年刊）,主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文,同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。     

广西桉树人工林配方施肥技术

2011年2月22日,由广西林科院土壤肥料研究所主持完成的"广西桉树人工林配方施肥技术研究与示范推广"项目通过了广西区林业厅组织的成果鉴定。本成果主要由"广西桉树人工林土壤肥力测定、评价及平衡施肥技术应用"、"桉树生理性缺素病症及防治措施研究"、     

《桉树科技》投稿须知

正《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊(季刊),主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文,同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。该刊及时反映了我国桉树研究的学术水平和发展方向,是从事桉树科技、科技推广、生产经营、教学等人员良好的专业性学术参考资料。欢迎广大同行踊跃投稿。     

《桉树科技》投稿须知

《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊(半年刊),主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文,同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。该刊及时反映了我国桉树研究的学术水平和发展方向,是从事桉树科研、科技推广、生产经营、教学等人员良好的专业性学术参考资料。欢迎广大同行踊跃投稿。     

《桉树科技》投稿须知

《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊（半年刊），主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文，同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。该刊及时反映了我国桉树研究的学术水平和发展方向，是从事桉树科研、科技推广、生产经营、教学等人员良好的专业性学术参考资料。欢迎广大同行踊跃投稿。     

《桉树科技》投稿须知

《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊（季刊），主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文，同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。该刊及时反映了我国桉树研究的学术水平和发展方向，是从事桉树科技、科技推广、生产经营、教学等人员良好的专业性学术参考资料。欢迎广大同行踊跃投稿。     

《桉树科技》投稿须知

《桉树科技》是由国家林业局科学技术司管理和国家林业局桉树研究开发中心主办、国内外公开发行的学术期刊（季刊）,主要刊登有关桉树引种、育种、种苗繁殖、营林技术、病虫害防治、木材加工与利用、人工林经营等方面内容的研究与综述科技论文,同时译介国外相关先进技术并报道有关桉树研究的科技活动动态及重大事件。该刊及时反映了我国按树研究的学术水平和发展方向,是从事桉树科技、科技推广、生产经营、教学等人员良好的专业性学术参考资料。欢迎广大同行踊跃投稿。     

桉树主要食叶害虫防治技术研究进展

介绍了我国桉树主要食叶害虫的种类和发生情况,描述了茶尺蛾、油桐尺蛾及同安钮夜蛾三种桉树主要食叶害虫的生物学特性,并从营林措施、化学防治、生物防治及林间施药技术等方面对桉树主要食叶害虫防治技术进行了探讨。     

我国桉树人工林改造技术研究综述

桉树作为速生树种，是国内木材的主要来源，具有较高的经济价值。但前期无节制的大面积种植，且种植技术不规范，导致桉树人工林土壤结构受到破坏、林下植物多样性下降，破坏生态稳定性，不利于桉树人工林的可持续发展。许多研究者对桉树人工林进行改造，以改善桉树人工林生态环境。该文通过查阅近20年国内桉树人工林改造技术研究文献，分析桉树人工林经营存在的问题及其造成的生态后果，评述桉树人工林改造技术，提出今后桉树人工林改造研究方向的建议。     

广西桉树无性系育苗产业化现状及其发展策略

介绍了广西在桉树组培和扦插技术方面的研究发展以及桉树无性系育苗产业化的现状,指出了当前桉树无性系育苗产业化中存在的主要问题,提出了深化桉树无性系育苗产业化的主要措施和策略。     

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。     

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.     

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.     

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.