森林衰退病研究现状及展望

文章对我国森衰退病的研究现状和发展概况进行了综述，并介绍了国外有关臭氧、酸沉降及森林衰退病与立地相关性等研究的重要进展。对于Manion的森林衰退病概念中的若干问题如非生物和生物因素的顺序、衰退病最终结果是导致树木死亡、森林衰退病的起因等进行了讨论。最后对我国森林衰退病研究提出了几点建议。     

攀枝花市凤凰木衰退病因的研究

对攀枝花市凤凰木衰退病发生原因的调查研究表明该病的发生是多方面因素共同作用的结果,归纳为诱发因子(predisposing factors),如空气污染严重、年降雨量分布不均匀、土壤粘重板结、土壤瘠薄等恶劣环境因素.激化因子(Inciting factors),受干旱严重重复发生的胁迫、霜冻及凤凰木夜蛾(Pericyma cruegeri)、尺蠖(Buzura suppresaria)等食叶害虫的年年严重危害.促进因子(Contributing factors)受凤凰木根腐病、端齿材小蠹(Xyleborus     

国外森林衰退病病原的若干概念

森林衰退病发生的原因，国外的学者对此有不同的见解，其致病因素也由单一因素发展到多种因素，因而在衰退病病原方面提出了若干的概念。该文就目前病原的几种概念进行简要叙述。     

樟子松衰退病现状及对策分析

论述了我国森林衰退病的研究和发展现状,通过对辽宁省樟子松衰退病现状的描述和分析揭示了樟子松衰退病的病因,结合玉佛山林业局实际工作中对樟子松衰退病的发生、发展、治理情况的监测,提出了防治樟子松衰退病的对策及建议。     

世界森林衰退病研究进展

森林衰退病是近代森林病理学出现的一个新概念,目前仍处于形成和完善阶段。文中综述了衰退病的基本概念及其病原研究进展,并指出了存在的问题与应用前景。     

国槐衰退病因的研究

对合肥市国槐衰退和枯死原因的调查研究表明，造成国槐衰退、枯死的原因是多方面因素共同作用的结果，是一种树木衰退病。该病发生的主要原因是：1诱发因素——土壤板结或透气性差、土壤污染(轻微)、根系裸露或深埋、树龄较大、枝梢害虫危害等；2激化因素——食叶害虫、土壤污染(中度)、机械损伤、干旱和积水等；3促进因素——腐烂和溃疡病菌、腐朽菌、蛀干害虫危害等。该研究结果为国槐衰退病的防治提供了理论依据，也为城市其他树木衰退或枯死原因的研究和防治提供参考。     

攀枝花市凤凰木衰退病因的研究

对攀枝花市凤凰木衰退病发生原因的调查研究表明：该病的发生是多方面因素共同作用的结果，归纳为诱发因子（predisposing factors），如空气污染严重、年降雨量量分布不均匀、土壤粘重板结、土壤瘠薄等恶劣环境因素。激化因子（Inciting factors），受干旱严重重复发生的胁迫、霜冻及凤凰木夜蛾（Pericyma cruegeri）、尺蠖（Buzura suppressaria）等食叶害虫的年年严重危害。促进因子（Contributiong factors）受凤凰木根腐病、端齿材小蠹（Xyleborus apicalis）、跗虎天牛（Perissus loetus）和吉丁虫（Coraebus sp.）等病虫危害。衰退的症状包括生长缓慢，叶稀疏、小型及歪曲，经常有缺绿的现象，叶脉变褐色，叶片过早变黄，过早脱落，直至死亡。     

橡胶树衰退与小蠹虫危害的关系

为害橡胶树的小囊虫种类增加,已由偶发性转变为常发性,导致橡胶树死亡,给生产造成巨大损失。本文借鉴防治云南松纵坑切梢小蠹(Tomicus piniperda L.)的经验教训,强调小蠹虫是一类“次期性”蛀干害虫,只有当橡胶树处于衰退状态才可能侵入为害。根据橡胶树既具有林木的共性又独具热带乔木作物的特殊性,运用森林衰退病理论,结合橡胶生产实际分析认为:橡胶树遭受风、雷、寒、病等灾害造成损伤、树皮溃烂、干枯是橡胶树小蠹虫危害的重要原因;橡胶树衰退则是小蠹虫危害的根本原因。     

园林植物衰退病及其防治

本文总结了园林植物衰退病的发生特点,系统全面地分析园林植物衰退病的各种可能致病因素,并对植物衰退病的科学诊断及其治理进行了讨论。     

泸水县核桃衰退原因分析

对泸水县核桃衰退及其气候、林分、病虫害进行调查和分析表明,泸水县核桃衰退是由非生物和生物因素综合引起的一种林木衰退病.诱发因子:气候变化、降雨量骤减、树龄偏大、林分结构和经营方式单一;激化因子:草履蚧、刺蛾、金龟子的为害;促进因子:豹纹木蠹蛾的为害、核桃枝枯病、腐烂病、溃疡病.     

福建省沿海木麻黄衰枯原因的研究

调查研究表明：福建省木麻黄衰枯现象是由多种因素引起的一种林木衰退病，其诱发因素主要是树种、种源的不适应，土壤肥力下降、水分失调：激化因素主要是星天牛、木毒蛾等虫害及风沙害；促进因素是引起木质部变色的次生病原菌。     

澳大利亚新南威尔士州台地上桉树的衰落

桉属植物是澳大利亚景观中的主要的乡土植物类群。在欧洲人定居澳大利亚以后,新南威尔士州台地的桉树急剧减少,桉树更新停滞,景观生态系统很难恢复到原初状态。本文介绍了桉树和乡土灌木减少的历史背景,分析了在这一地区幼苗更新减少的原因主要是由于开垦、放牧、火烧、外来物种竞争、枯萎、昆虫和干旱等,总结了桉树更新的可能条件,如幼苗存活的合适条件、充足的种子供应、避免捕食、适当的萌发条件、无放牧环境、机械处理、杂草控制、火烧系统和疾病控制等,借以建议在该地区应怎样保护和促进桉树的更新。参26。     

沿海木麻黄衰退机理与维护途径的研究进展

基于几十年来木麻黄的研究成果，综述了沿海木麻黄林的衰退因素。结果认为：沿海木麻黄衰退现象是由多种因素引起的一种林木衰退病，并指出维持木麻黄林健康的主要途径是营造混交林以及选用抗病、抗旱（风）等抗逆无性系造林。     

Fungi associated with above-ground portions of declining oaks (Quercus robur) in Germany

Various disease symptoms on oak (Quercus robur L.) affected by oak decline in northern Germany were examined for fungal colonization. The isolated fungi are evaluated in respect to their possible pathogenic qualities and the results are compared with those of other authors and geographic regions.     

发育林下植被是恢复杉木人工林地力的重要途径

论述我国中亚热带杉木盛产区，通过间伐发育林下植被，改良土壤理，化性质，提高森林土壤生物活性，从而为通过合理的森林经营，发育林下植物群落，维护和提高森林土壤肥力，改良杉木人工林地力衰退，提供可靠的科学数据和途径。     

Requirements and biological aspects of Fusarium eumartii and its possible role in oak decline in North-eastern Italian oak forests

To determine a possible role of Fusarium eumartii in oak decline in different zones of Italy some requirements (temperature, substrates, pH) and some biological aspects (ability to produce phytotoxic metabolites, and pathogenicity) were studied in vitro and by inoculation tests on oak seedlings.     

当涂县古树名木资源及保护复壮技术

古树名木是宝贵的物产资源,是维系生物物种多样性和物种固有基因库的主要内容。本文对当涂县的古树名木进行了专项调查,分析了古树名木生长衰退的原因,提出了切实可行的复壮措施。     

Effects and etiology of sudden aspen decline in southwestern Colorado,USA

Sudden aspen decline (SAD), affecting Populus tremuloides, was first observed in Colorado in 2004. By 2008 it affected at least 220,000 ha, an estimated 17% of the aspen cover type in the state. In southwestern Colorado, we examined site and stand features in paired healthy and damaged plots to assess the effects of SAD on aspen and to identify factors associated with decline. Root mortality increased significantly with recent crown loss. Consequently, density of regeneration did not increase as the overstory deteriorated, and regeneration that originated since 2002 decreased significantly in stands with moderate to severe SAD. However, mortality of regeneration did not increase with that of the overstory. Remeasurement of a subset of plots after 1–2 yrs showed significant increases in severity. Contrary to expectations, overstory age and diameter were not related to SAD severity as measured by recent crown loss or mortality. Severity of SAD was inversely, but weakly, related to basal area, stem slenderness, and site index, and positively related to upper slope positions. This is consistent with moisture stress as an underlying factor. To test the role of climate as an inciting factor for SAD, a landscape-scale climate model was used to compare moisture status of declining and healthy aspen at the height of the warm drought in water year 2002. Polygons identified as damaged aspen in the 2008 aerial survey had greater moisture deficits than healthy aspen in the 2002 water year. SAD has led to loss of aspen cover in some stands, and is occurring in areas where early loss of aspen due to climate change has been predicted. Further warm, dry growing seasons will likely lead to recurrence of SAD.     

Dendroecological assessment of the complex causes of decline and recovery of the growth of silver fir (Abies alba Mill.) in Southern Germany

Causes of decline and silver fir (Abies alba Mill.) mortality in Central Europe have been controversially discussed for a long time. This contribution details a comprehensive dendroecological investigation of two basic and alternative hypotheses that explain the decline by either climatic influences or by SO₂ pollution as the primary factors. Growth reduction between the 1960s and 1980s as well as the recovery of growth during recent decades have be seen as a response to complex interactions of multiple factors. Herein, we undertake a multidisciplinary evaluation of a broad database, representing the long-term growth of 1010 firs from 51 sites, long-term climate records as well as data assessing the long-term pollution situation in Southern Germany. The results provide clear evidence that SO₂-immissions play a key role in decline and that tree growth corresponds with the regional and temporal pattern of SO₂ pollution. Calculations with a new complex growth model indicate that tree-ring widths of fir at many sites were more influenced by SO₂ than by any other growth-determining factor during the second half of the last century. Strongest coherence between measured and modelled ring widths are found if – in addition to temperature, available soil water content, heavy frost events and long-term growth trends – the site-specific trend of SO₂ pollution is included. Both the immediate response to SO₂ pollution and the quick recovery of fir since the beginning of the 1980s after the decrease of SO₂ emissions indicate a direct impact of SO₂ in gaseous form and not via the soil in terms of soil acidification. Tree-ring widths document that radial growth response occurs at air concentrations above 10 μg SO₂ m⁻³ (annual average), which can be thought of as a critical threshold for silver fir health. Since the beginning of the 1980s, increasing growth trends have been observed which predominantly result from decreased SO₂ pollution in most parts of Central Europe, although climate change, fertilization by nitrogen deposition and a reduced tree-to-tree competition are also relevant factors. The drastic reduction of SO₂ emission during the recent decades significantly improved the environmental conditions for fir. Consequently, an increased cultivation of silver fir on suitable sites is recommended.     

Do changes in spatial distribution, structure and abundance of silver fir (Abies alba Mill.) indicate its decline?

Silver fir decline was investigated based on changes in spatial distribution of fir, fir abundance in forest stands, dbh (age) structure of fir, and abundance of fir regeneration. The authors used a large-scale approach to study the dynamics of silver fir over nearly 40 years. Based on Silva-SI, a spatial information system, the majority of total forest area in Slovenia was analysed for changes in the distribution of silver fir in the period 1970-2008 using artificial neural networks (ANNs), with respect to site, stand, and forest management variables. Additionally, changes in abundance of silver fir (hereafter fir) in the same period were analysed with a general linear model, while changes in the dbh structure of fir and fir regeneration were analysed with non-parametric tests. Most selected indicators confirmed the hypothesis of fir decline in the period 1970-2008, as evidenced by a reduction in the area of forests with a share of fir in the total growing stock >25% (from 18.9% to 9.5% of total area), a reduction in the share of fir in the growing stock of forest stands (from 17.5% to 7.5%), ageing of the fir population, and a disproportionate share of fir saplings in the total saplings relative to fir's share in the growing stock of forest stands. A 1.5% increase in fir distribution area in the observed period contradicts the decline hypothesis. ANNs showed that the spatiotemporal dynamics of fir was most affected by four variables: forest type, share of fir in the potential natural vegetation, mean annual precipitation, and mean annual temperature. The latter two, together with the growing stock at the start of study period, the degree of connectivity between fir stands, and bedrock type, were significant predictors of decline of fir abundance in forest stands. Significant differences in spatiotemporal dynamics and changes in fir abundance were found between forest types representing a complex of site conditions and past forest management. A further decline of abundance of fir on a large spatial scale in the next decades is expected. Conservation of fir in forest stands will depend mainly on the successful regeneration of fir and sufficient recruitment.