干热河谷区滇刺枣生物学特性

干热河谷区滇刺枣生物学特性喻赞仁关键词干热河谷，滇刺枣，生物学，信德紫胶虫滇刺枣（ＺｉｚｉｐｈｕｓｍａｕｒｉｔｉａｎａＬａｍ．）是信德紫胶虫（Ｋｅｒｒｉａｓｉｎｄｉｃａ（Ｍａｈｄ．）］的主要寄主植物，我国以台湾省和云南省分布最广。在云南以怒江、金沙江...     

滇刺枣地理种源试验初探

滇刺枣地理种源试验初探汪云关键词滇刺枣，地理种源，发芽试验滇刺枣（ＺｉｚｙｐｈｕｓｍａｕｒｉｔｉａｎａＬａｍ．）系鼠李科落叶乔木，是目前我国从国外引进的优良紫胶虫种之一——信德胶虫（ＫｅｒｒｉａｓｉｎｄｉｃａＭａｈｄ．）的主要寄主。随着信德胶虫在我国...     

三种紫胶虫胶质比较研究*

三种紫胶虫胶质比较研究李金元，赵玉兰，李义龙，黄维垣关键词紫胶虫，紫胶树脂，原胶质量我国生产上主要放养三个紫胶虫种［１］：紫胶虫〔Ｋｅｒｒｉａｌａｃｃａ（Ｋｅｒｒ）〕、信德紫胶虫〔ｋｅｒｒｉａｓｉｎｄｉｃａ（Ｍａｈｄ．）〕和中国紫胶虫〔Ｋｅｒｒｉａｃ...     

紫胶虫雌成虫玻片标本制作方法改进*

紫胶虫雌成虫玻片标本制作方法改进在紫胶虫［Ｋｅｒｒｉａｌａｃｃａ（Ｋｅｒｒ）］玻片标本的制作中，尤以紫胶虫雌成虫难度较大。原因在于雌成虫体液多、虫体小、体型各异，有囊形、近球形、锥形和纺锤形等，加之又不能损伤其主要器官形态特征，如背刺、背突、膊器、肛...     

紫胶蚧对寄主适应性的初步研究

紫胶蚧（Ｋｅｒｒｉａｌａｃａ（Ｋｅｒｒ．））是目前最优良的紫胶虫种。该虫的适生区为热带和南亚热带的低海拔地区,最优良寄主是久树（ＳｃｈｌｅｉｃｈｅｒａｏｌｅｏｓａＬｏｕｒ．）。紫胶虫泌胶与寄主的营养成分等有着较密切的关系,国内外都有一定的研究［１～５...     

滇刺枣五个地理种源的同工酶分析

滇刺枣五个地理种源的同工酶分析＊汪云马显达关键词滇刺枣地理种源同工酶滇刺枣（ＺｉｚｉｐｈｕｓｍａｕｒｉｔｉａｎａＬａｍｋ．）是鼠李科（Ｒｈａｍｎａｃｅａｅ）枣属（Ｚｉｚｉｐｈｕｓ）落叶乔木，为一种新兴的多用途经济树木。在长期的天然杂交和地域隔绝下，形...     

对几种寄主树种放养4号胶虫的研究

目前我国被发现或被利用于优良紫胶虫种４号胶虫（Ｋｅｒｉａ ｌａｃｃａ）的优良寄主植物种类较少,制约了我国优质紫胶的发展。对苏门答腊金合欢（Ａｃａｃｉａ ｍｏｎｔａｎａ ｖａｒ．ｓｕｍａｔｏｒａｎａ．）、光叶合欢（Ａｌｂｉｚｉａ ｍｅｙｅｒｉ）、复羽叶栾树（Ｋｏｅｌｒｅｕｔｅｒｉａ ｂｉｐｉｎｎａｔａ）的放胶虫试验结果表明,这３种树种可以作为４号胶虫的良好寄主予以利用或推广。     

滇刺枣不同种源试放4号紫胶虫研究

对在滇刺枣７个不同种源树上试放４号紫胶虫研究发现,４号紫胶虫在滇刺枣树上亦能正常完成其生活史,大部分种源能获得丰厚的虫胶。其中,元谋和双柏两个种源,放收比在１∶５以上;胶被厚在０５ｃｍ以上;怀卵量在２５０～３１１之间。试验为扩大４号紫胶虫的优良寄主种类提供了科学依据。     

滇刺枣不同种源试放4号紫胶虫研究

对在滇刺枣７个不同种源树上试放４号紫胶虫研究发现,４号紫胶虫在滇树刺枣树上亦能正常完成其生活史,大部分种源能获得丰厚的虫胶。其中,元谋和双柏两个种源,放收比在１：５以上;胶被厚在０．５ｃｍ以上;怀卵量在２５０－３１１之间。试验为扩大４号紫胶虫的优良寄主种类提供了科学依据。     

甘肃古树名木调查研究

据甘肃省林学会组织实地调查，全省古树树种达４０余种，分属１９科２７属。主要有：银杏。（Ｇｉｎｋｇｏ ｂｉｌｏｂａ Ｌ）、紫果云杉（Ｐｉｃｅａ ｐｕｒｐｕｒｅａ Ｍａｓｔ．）、青海云杉（Ｐ．ｃｒａｓｇｉｆｏｌｉａ Ｋｏｍ．）、青杆（Ｐ．ｗｉｌｓｏｎｉｉ Ｍａｓｔ．）、油松（Ｐｉｎｕｓ ｔａｂｕｌａｅｆｏｒｍｉｓ Ｃａｒｒ．）、白皮松（Ｐ．ｂｕｎｇｅａｎａ Ｚｕｃｃ．）、侧柏（Ｐｌａｔｙｃｌａｄｕｓ     

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.