吉林省品种杨基因收集圃品种(系)抗寒性评价研究

在吉林省双辽黑钙土型沙土上建立品种杨基因收集圃并进行抗寒性测定,结果表明:参试的88个品种(系)中,抗寒性大于对照白城小黑杨的有11个品种(系),分别为:98-34号杨、7915501杨、47号杨、18号杨、小×加暴638杨、摩里柏林杨、白城2号杨、大同86-12杨、7号杨、富锦4号杨、迎春5号杨,是吉林省品种杨杂交育种可选用的较理想抗寒亲本。     

吉林省品种杨品种(系)抗病性评价研究

在吉林省双辽品种杨基因收集圃中对参试的88个品种(系)进行抗病性测定,结果表明:抗叶锈病品种(系)为小×钻杨、白林2号杨、富锦3号杨、5号杨、晚花杨、西+加杨、迎春5号杨、81-10号杨、中林299杨、里普杨、7号杨、W-14杨、18号杨、长春加拿大杨、加型杨、2号杨、昭林200杨、白城42号杨、黑林2号杨、黑林1号杨、辽育2号杨、黑×小(选)杨、86-24号杨、1号杨、加×美杨,抗黑斑病品种(系)为西+加杨、白林3号杨、迎春5号杨、W-14杨、小×钻杨、晚花杨、加雌杨、88-13号杨、98-22号杨、33号杨、47号杨、大凌河220杨、辽育2号杨、加×美杨、中林299杨、山海关杨、黑林1号杨、吉林加拿大杨、鲁山杨、5号杨、美×中杨、83-25号杨、摩里佛拉健杨、白城4号杨、黄快杨、黑×小(选)杨、马里兰德×小黑杨、81-10号杨、加型杨、荷兰3934号杨、(美×黑)×健杨、莫斯科加拿大杨、新生×小黑50杨、小×加暴638杨、长春加拿大杨、舍伯吐杨、美×小47杨、龙荷夫健杨、107号杨、格尔里杨、小青×美杨、富锦3号杨、98-30号杨、白城41号杨、健杨、黑×19杨、白城42号杨、N119杨、86-24号杨,以上是吉林省品种杨杂交育种较理想的抗叶锈病及黑斑病亲本。     

品种杨基因收集圃品种(系)适应性评价研究

在吉林省双辽黑钙土型沙土上建立品种杨基因收集圃并进行适应性栽培试验,结果表明:在88个品种(系)中,苗期(1 a生)成活率大于对照白城小黑杨(85.3%)的有10个品种,分别为晚花杨(94.0%)、新生×小黑52杨(91.3%)、白城41号杨(88.7%)、83-25杨(87.4%)、莫斯科加拿大杨(86.7%)、加×美杨(86.7%)、88-04杨(86.7%)、98-33杨(86.7%)、黑林2号杨(86.7%)、小×钻杨(85.6%)。半轮伐期(12 a生)保存率大于对照白城小黑杨(85.33%)的有2个品种,分别为7915501杨(91.67%)和白林3号杨(87.50%);与对照表现持平的有1个品种,即新生×小黑52杨(85.33%)。     

吉林省品种杨品种(系)抗虫性评价研究

对参试的品种杨88个品种(系)苗期和幼龄期的抗虫性进行测定,结果表明:抗白杨透翅蛾的品种(系)为白城5号杨、白林3号杨、白林2号杨,是品种杨杂交育种较理想的抗白杨透翅蛾亲本;抗青杨天牛的品种(系)为白林2号杨、白城41号杨、迎春5号杨、格尔里杨、107号杨、中黑防2号杨、88-04杨、吉林加拿大杨、白城1号杨、晚花杨、加雌杨、健杨、白城2号杨、88-13杨、摩里柏林杨、81-10杨、白林3号杨、5号杨、小×钻杨,是品种杨杂交育种较理想的抗青杨天牛亲本。     

吉林省中部平原地杨树品种选择试验研究初报

吉林省林科所从1981年起在东丰、太平池两地以32个杨树品种(系)进行了杨树品种选择试验,现已选出加拿大杨(♀)等适合我省中部平原栽培的速生、抗性强的优良品种,特别是加拿大杨(♀)单株材积不仅超小黑杨36.8％,而且在两试验区中都未发生干皮冻裂和烂皮病。     

杨树杂交育种试验的几点体会

为了选育出适合我省中东部平原及山区,生长快、材质良好,抗性强的优良杨树品种,我们在室内、温室、共做了42个杂交组合,其中31个组合得到了杂交苗,最后获得了杂交苗4483株,在圃地初选出43棵优良单株。这些杂交组合的亲本,主要利用省内外较速生的优良品种,做为母本的有:毛白杨、加杨、沙兰杨、小钻、香杨、黑(杂)、小叶杨、小叶杨(河北)、小青杨等9种,做为父本的有:山杨、P_(15)A、加杨、美×     

玛引14号杨、玛引3号杨材积 增长量达到我区杨树速生丰产先进水平

杨树是我区的重要速生用材树种,为了选出适合新疆北疆地区速生丰产的杨树品种,我场和新疆八一农学院合作,于1975年4月,营造了50亩杨树品种汇集圃。共栽植有玛引14号杨、玛引3号杨、合作杨、健杨、北京杨、莫斯科杨等161个品种(品系)。经过10年试验取得了显著效果,玛引14号杨、玛引3号杨生长最快,材积增长量达到北疆地区     

几个杨树优良品种光合净生产力的测定

通过半叶法,测定了小黑杨、黑林1号杨、拟青杨×山海关杨、中黑防1号杨、银中杨等5个杨树优良品种的光合速率、净生产力,结果表明:几个品种光合净生产力差异明显,生长量最优的品种为拟青杨×山海关杨。     

几个主要杨树品种生长节律的研究

我们从1984年开始,连续二年在省森林植物园速生丰产林中,对小黑14等五个品种的杨树生长节律进行了调查研究。并对观测数据进行统计分析,试图用数量来表示在年周期内,各阶段(以旬计)树高生长量变异程度,确定各品种生长的高峰期,以便更合理地采取速生丰产措施,加快速生丰产的进程。     

无絮杨树品种的定向选育研究

本研究针对解决杨树城乡造林绿化结种飞絮问题为目的,选育无絮、速生、抗虫性强的品种定向培育,既可获得速生丰产,又可根除飞絮之害。通过从天然杂交实生后代选优及引进的优良无性系中的无絮品种进行树高、胸径、冠幅生长量及对桑天牛的抗性进行比较试验,结果表明:汉选1号、汉选2号、汉选4 号、中新1 号等无絮品种生长量均比对照品种Ⅰ-69 杨大,可用于城乡绿化造林。     

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.     

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.     

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。