杨树苗期主要病害及防治方法

杨树苗期主要病害包括:叶部病害、干部病害和根部病害三类。根据各种病害的发生规律,提出了病害的防治措施,清除圃地病残体、土壤消毒处理等方法是遏制杨树苗期病害的主要途径。     

祁连山森林病害种类调查简

系统调查了祁连山自然保护区森林病害种类，采到罹病林木11科22种（属），鉴定出林木病原107种，引起病害134种。病原分类分别为真菌83种、螨类6种、寄生植物3种、细菌1种，生理性病原14类。病害种类按寄生部位分，叶部病害74种，干部病害38种，枝梢病害17种，种实、根部病害较少。按树种分，青海云杉病害23种，青杄病害13种，人工栽培杨树病害18种，山杨病害18种，桦树病害10种，山柳病害8种，华北落叶松病害6种，祁连圆柏病害5种，油松病害5种，梅属植物病害5种，苹果属植物病害3种，小檗属植物病害4种，杜鹃类病害3种，忍冬病害2种，其他林木病害8种。     

中国东北地区林木真菌病害地理分布概述

本文对我国东北地区林木真菌病害的地理分布进行了初步研究和区划，将东北林木真菌病害划为七个区，即大兴安岭北部用材林病害区、呼伦贝尔草原护牧林病害区、大兴安岭南部防护林用材林病害区、松辽平原农田防护林病害区、小兴安岭用材林病害区、三江平原农田防护林病害区及长白山用材林水源林病害区。并对每一区的自然概况、病害种类和特点进行论述。     

中国东北地区林木真菌病害地理分布概述

本文对我国东北地区林木真菌病害的地理分布进行了初步研究和区划，将东北林木真菌病害的为七个区，即大兴安岭北部用材林病害区，呼伦贝尔草原护牧林病害区，大兴安岭南部防护林用材林病害区，松辽平原农田防护林病害区，小兴安岭用材林病害区，三江平原农田防护林病害区及长白山用材林水源林病害区。并对每一区的自然概况，病害种类和特点进行论述。     

广西速生丰产桉树病害调查

对广西速生丰产桉树Eucalyptus spp.进行了比较系统、全面的传染性病害调查,共鉴定出30种传染性病害,即15种主要病害和15种次要病害。其中4种主要病害和8种次要病害为广西新记录病害。对主要病害的症状特点和危害程度进行了描述,并提出综合治理建议。     

荆州地区杨树病害调查研究

杨树病害严重影响着杨树的正常生长发育。自1990年以来,我们对荆州地区的杨树病害作了全面调查,结果表明,造成危害的主要有八种病害,其中叶部病害二种、干部病害三种、根部病害一种、生理性病害二种,为此,我们就这些病害的病原、致病机制及防治措施等进行了研究。     

璧山区园林植物病害种类调查初报

2016~2017年对重庆市璧山区园林植物病虫害进行了实地调查,共发现15种病害。统计了各种病害的发生程度、发病时期。结果表明:其中真菌性种类多,其次是生理性病害。细菌性病害、病毒性病害则没有调查记录,但园林病害中细菌性病害也较多。此调查结果能对丰富园林植物病害种类、病原菌种质资源库提供参考。     

针叶树苗圃病害调查与主要病害发生规律研究

本文调查了针叶树苗期病害的种类和苗期病害的发生规律，结果表明针叶树苗期病害有8种，其中侵染性病害有6种，生理性病害有2种。猝倒病是针叶树苗期主要的病害，表现为3种症状类型。日灼型猝倒是气象性病害的主要形式，由丝核菌Rhizoctonia和镰刀菌Fusarium引起的生物猝倒型和立枯型病害是针叶树育苗的主要病害，其发生与育苗地所处的环境、营养土基质有关,同时提出了对针叶树苗期病害防治的对策。     

黑龙江省西部平原缓丘农区杨树病害种类及主要病害防治

本文记载了黑龙江省西部平原缓丘农区杨树病害种类 2 1种 ,其中 :苗木病害 6种、枝干病害 8种、叶部病害 6种、根部病害 1种。并提出了几种重要病害的综合防治措施     

沈阳地区银杏病害的种类及其防治措施

通过对沈阳地区银杏病害的全面普查和分类鉴定,在银杏树上共发现了13种病害。按病原可分为真菌性和生理性2大病害类别。其中真菌病害11种,是较大的一个类别,生理性病害2种。叶部病害所占比例较大。银杏病害的发生多集中于春、夏两季,高温、高湿条件下发病重,立地条件差或管理粗放病害重。与此同时,该文还提出了病害防控应把握的几个关键环节。     

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.     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.