日本落叶松嫩枝扦插育苗技术的研究

结果表明：采用５５年生以下母树嫩枝扦插生根率达８０～９８％；扦插苗春季移栽成活率达９７％；２年生扦插移栽苗平均高５７．８ｃｍ，平均地径０．８ｃｍ，９０％以上的苗木可用于造林。     

良种沙棘嫩枝扦插容器育苗及造林试验研究

在全光雾嫩枝扦插育苗试验的基础上，采用网袋状轻型基质育苗容器进行容器育苗试验，结果表明，容器扦插平均生根率可达95％以上，较普通全光雾沙床扦插对照(CK)提高5．75％，主根数、虚根数均较对照(CK)增加1．02条，5．86条，平均苗高、地径分别增加4．33cm，0．07cm；容器扦插苗用于造林，其成活率较对照(CK)增加25．0％，当年株高、地径生长量较对照(CK)增加18．70cm，0．30cm；而且容器苗便于运输，可在整个生长季节随时移栽。     

Guadua amplexifolia 种苗扩繁技术初探

以引进竹种Guadua amplexifolia为对象，进行了种苗林竹丛结构调控、全年连续育苗和主枝、次生枝扦插育苗试验，结果表明：种苗林竹丛结构调控对提高新竹质量有显著作用，处理较对照新竹径级增大51．5％，立竹全高增加30．9％；全年3次移栽育苗成活率均达87％以上，其中以5月份移栽效果好，成竹率达45．7％；1年生、2年生立竹主枝、次生枝扦插成活率68％以上，各处理生根时间无显著差异，平均为47d，综合扦插成活率、出笋成竹数、新竹地径等，以2年生立竹主枝扦插效果最佳。     

龙脑樟树快繁育苗技术的研究与应用

研究表明，选用插穗长6—8cm、粗0．2—0．5cm的优树萌条及半木质化的嫩枝，在春、夏、秋3季扦插，在插前土壤采用0．5％KMnO4液消毒，插穗采用1000mg/kg IBA或50mg/kgABT溶液处理，扦插后覆盖遮荫网，保持棚内相对湿度85％-95％，加强肥水、苗圃田间管理等配套技术，一般25—30d长出愈合组织产生新根，60d后新根达3-5cm时即可移栽。幼苗成活率一般为80％-85％，最高达90％以上。该技术扦插育苗，不仅成活率高，幼苗生长整齐，成本低，经济适用，操作简单;而且后代个体遗传性状稳定，为龙脑樟树快速育苗开辟了新途径。     

刺槐无性系营养钵及硬枝扦插育苗试验

为加速刺槐的良种化进程,用细根段刺槐根系和硬枝扦插进行育苗技术研究,提高良种繁殖率。用粗0．5 -0．8 cm的根段进行钵插育苗一般成活率可达85％以上,当年平均苗高和地径达2．5 m和2 cm以上,苗木出圃率达90％以上;利用ABT生根粉100 mg／kg进行硬枝扦插处理24 h效果最佳,扦插成活率、地径和苗高与对照相比分别高71．6％、28．9％和28．6％。     

白榆嫩枝扦插技术的研究

通过三年试验，利用全光喷雾扦插育苗技术和ABT生根粉促根处理，成功地解决了白榆嫩枝扦插生根和移栽成活问题，使白榆无性繁殖技术取得了突破性的进展。其扦插生根率达到95％以上，移栽成活率达到90％以上、当年生扦插移栽苗高度达1．0米以上，翌年6月达到2．0米的成苗标准，比播种育苗缩短1／3的育苗周期。     

翅荚木轻基质秋季育苗技术研究

以顺昌县次生种源翅荚木种子为繁育材料,探讨不同基质配比、热水浸种催芽、移栽时期、施肥浓度对翅荚木秋季轻基质容器育苗的影响,并对比分析春季大田与秋季基质容器育苗的苗木生长及造林效果.结果表明,翅荚木秋季容器育苗比春季大田育苗缩短育苗期,减少育苗和造林成本,提高造林成效.以泥炭：椰康：珍珠岩配比为4：2：1的基质、80℃热水浸种催芽、种子露白点播及采用1％浓度复合肥追肥,育苗效果最好,当年平均苗高31.23cm,平均地径0.25cm,苗木出圃率90.0％,次年即可上山造林,成活率达98.0％.     

冬枣弓棚绿枝扦插育苗技术

利用冬枣绿枝扦插育苗，有效地解决了枣树良种快繁问题，扦插生根率和移栽成活率分别达到93％。7月25日移栽大田的扦插苗当年平均高生长22．5cm，4－5个分枝，最高为32cm。     

河南白榆扦插育苗与造林技术

白榆的育苗和造林大多采用播种方法,近年来,我圃采取扦插方法育苗、造林,成活率可达80—90％,且苗木生长较快。据1980年11月对当年生扦插苗和播种苗的生长调查,扦插苗平均高1.05米,平均地径0.85厘米;播种苗平均高0.87米,平均地径0.64厘米。扦插后能保持河南自榆(母树)干形直、抗性强等优良性状。一、种条的选择、采集和处理     

白榆嫩枝扦插技术

通过３年试验，利用全光喷扦插育苗技术和ＡＢＴ生根粉促根处理，成功地解决了白榆嫩枝扦插生根和移栽成活问题，其扦插生根率达到９５％以上，移栽成活率达到９０％以上，当年生扦插移栽苗高度达１．０ｍ以上，翌年６月达到２．０ｍ的成苗标准，比播种育苗缩短１／３的育苗周期。     

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.     

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.