杨树新品系苗期遗传性状测试评价

在4个地点,对14个杨树新品系二根一干苗进行了6项性状指标综合测试评价,综合性状表现优良的品系有中M、50、53、B、J、5号杨,苗高、胸径生长量较对照小黑杨提高47.21%~25.65%、88.89%~38.27%,锈病指数较小黑杨降低9.63~13.04。     

杨树新无性系苗期叶面形态指标测试

通过在黑龙江省牡丹江市4个地点,对杨树14个品种的苗期叶面8项性状指标进行测试,综合评价试验结果[1]表明:单株叶面积以中M为最大,中H、LC、LB、01号杨次之;单株叶重以中M为最重,LC、中H、01、LB号杨次之;不同品种间单株叶面积、单株叶重、单叶面积等8项指标均存在显著差异,而且地点×品种交互作用差异也极显著。     

沙区杨树引种与选择试验初报

通过在辽宁章古台风沙区对 2 4个杨树无性系的苗期观察和造林对比试验 ,对不同品系的生长量、抗逆性进行了调查和综合分析。选育出生长量较高、抗性较强的优良品系 5个 ,即 :白城4 1、通选 0 90 - 1、黑林 1号、锦县小钻杨、喀左小钻杨     

杨树新品系苗期多性状主成分及聚类分析

采用权重法计算15个杨树新品系,16个性状的综合主成分值,并对其进行聚类及邓肯新复极差检验分析,结果表明:中M、53、J、50、B、A号杨综合主成分值较大,处在生长速度快及抗寒性强的第V和第Ⅳ类群,属于综合性状表现优良的品系,且分析结果与原始数据直观反映结果一致.     

7个杨树无性系苗期选育试验初报

为实现杨树多品系造林，筛选出适宜本地区生长、抗性强、速生丰产的优良无性系，为辽宁杨的品种更替作好基础工作，我们对“７８－７”等７个杨树无性系进行了苗期选育试验。１试验地概况试验地位于凌海市大凌河林场大来号分场。东经１２０°４２′，北纬４０°４８′，海...     

美洲黑杨杂种无性系抗病性研究

对美洲黑杨与青杨派树种杂交及美洲黑杨种内杂交所选出的几个生长快、适应性强的无性系,作了锈病、黑斑病、溃疡病的抗性研究。结果表明:这些无性系绝大部分为抗病或高抗,少数为感病。其中对这3种病害均表现抗病或高抗的有69杨×美洲黑杨的5个无性系;06号、52号、57号、66号、80号及69杨。对锈病感病的有69杨×青杨的两个无性系:142号、1062号及69杨×小青杨的592号无性系;高感的有69杨×小叶杨的216号无性系。对黑斑病高感的有Ⅰ—214杨×北京杨的01号无性系及214杨、沙兰杨。     

杨树品种苗期叶部抗病性调查

通过对杨树不同品种苗期感病性调查发现,创新杨、82-130杨、桑巨杨、313杨等较抗杨树黑斑病;OP-367杨等较抗角斑病;82-133杨、599杨、82-130杨、G2杨等较抗锈病;2001杨、OP-367杨、50杨、欧黑杨、天演杨、599杨、创新杨、桑巨杨、WQ156杨、WD540杨、313杨、G2杨等较抗黑星病。还对不同品种抗白粉病情况进行了调查。     

欧美杨细菌性溃疡病菌的寄主范围调查及其寄主抗性物质的初步分析

[目的]为明确欧美杨细菌性溃疡病菌的寄主范围、欧美杨抗性品种及其可能的抗性活性物质。[方法]通过田间接种方法开展欧美杨细菌性溃疡病菌的寄主范围、杨树品系抗性调查,并利用高效液相色谱分析杨树抗感品种树皮中活性物质含量及其染病前后含量变化情况,同时利用抑菌实验验证潜在抗性物质的活性。[结果]研究发现欧美杨细菌性溃疡病主要危害黑杨派美洲黑杨、欧美杂交杨的品系以及旱柳,而欧洲黑杨品系具有高度抗菌能力;本研究的30个美洲黑杨和欧美杂交杨品系中,中林46杨、2025杨、2001杨、313杨、中荷1号杨和16-09杨是高感病品系;16-10杨、豫抗1号杨为高抗病品系,而131杨、03-59杨、02-212杨和03-34杨为抗病杨树品种;杂交柳和垂柳抗病,金丝柳轻微感病;栎属和青杨派的种类和品系具有高度抗性。高效液相色谱分析显示,抗病和高感病品系树皮中的邻苯二酚、苯甲酸、绿原酸、儿茶素的含量较高,其中邻苯二酚和儿茶素在病菌侵染时含量明显增加。[结论]明确了欧美杨细菌性溃疡病的主要危害对象和寄主范围,明确了具有抗性、感病的杨树品系,证明了邻苯二酚和儿茶素与杨树抗病性密切相关,该研究结果为欧美杨的栽培和病害防治提供技术支持和防治建议,该研究结果对我国欧美速生杨的细菌性溃疡病的防治具有重要意义。     

中雄4号杨选育研究

从中国林业科学研究院林业研究所引入39个美洲黑杨×甜杨杂交无性系,在黑龙江西部高纬度高寒地区对各无性系苗期生长、越冬及抗病虫性等性状进行多年测试,选择繁殖能力强、苗期长势好、无严重病虫害、抗逆性强、能安全越冬的优良品系进行大量繁殖,建立品系评比林进行复选。经20 a时间,开展苗期品系评比、区域试验与示范,筛选出杨树新品种中雄4号杨(Populus deltoides×P.suaveolens)。该品种为雄株,具有树干通直圆满、速生、材质好、耐寒、抗旱、抗病虫和不飞絮等优良特性,适合作纸浆材等工业用材林、防护林及绿化树种。     

辽宁杨遗传改良的研究

利用速生性强的美洲黑杨品系辽宁杨为母本,进行种内地理远缘遗传改良,通过人工控制授粉、苗期选择、区域栽培试验、示范林栽培以及实验室测试等12年的综合研究,选育出了9317、9318新杂种无性系均属雌株,它们性状相似,]辽育3号杨(Porulus deltoidescv.Liaoyu3)。辽育3号杨综合了父母本的速生、抗性强的优良特性,材质及制浆性能也比较优良。2004年12月由辽宁省科学技术厅主持,对该成果进行鉴定为达到国际先进水平。     

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.