Occurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees

Soil‐borne species of Phytophthora were isolated from 19 of 30 examined oak forest areas in Italy. The frequency of isolated Phytophthora spp. (35.2%) was significantly correlated with soil pH and longitude of the sites. Eleven Phytophthora species were detected. Phytophthora cambivora, P. cinnamomi and P. cactorum were recovered from sites in central and southern Italy whereas P. quercina was isolated in the northern and central part of the country. Phytophthora citricola occurred all over Italy. Phytophthora quercina was the only species significantly associated with declining oak trees.     

浏阳市永安乡板栗疫霉菌病的研究

湖南省测阳市永安乡1994-1997年营造板栗林近270hm^2,2000～2003年发生大面积枯死．经研究是板栗疫霉菌所致的板栗疫霉菌病所造成。此病的病原和发生规律与日本人猪崎政敏和中国农科院果树研究所报道的情况相吻合。本文中，以病原物命名，称板栗疫霉菌病，与林业部检疫局所定的“疫病”相区别。     

贵州兰科植物新记录（Ⅱ）

本文报道贵州产兰科植物新分布20种1变种，分别属于15个属的种类。     

Dothistroma pini Hulbary: A New Disease on Pine in Britain

Dothistroma pini Hulbary, not hitherto reported in Britain,is described. Since 1954, and possibly before this date, ithas caused serious defoliation of nursery pine stock, particularlyof Pinus nigra and P. ponderosa. It has been reported only fromtwo nurseries both in the Wareham area, Dorset, but the reasonfor this extremely limited distribution is unknown. Attacksare worst in wet summers. Spore inoculations on potted plantsgave severe infection.     

福建8种维管束植物分布新记录

本文增补了《福建植物志》未记载收录的8种维管束植物,它们是:稀子蕨、华南青皮木、乐昌含笑、灰毛含笑、雅致含笑、香港黄檀、密花豆藤、青木。     

Effect of density of trees on drag exerted on trees in river channels

Recently, riparian forests have attracted attention as they are effective for ecological preservation and landscape enhancement. Uses of such forests in flood prevention, sediment control, and erosion control works have been actively promoted. This study aims to clarify the effect of density of riparian trees on drag exerted on trees along river channels under the regime of bed load transport. Hydraulic model experiments were performed using a straight channel, and the methods to calculate the drag coefficient necessary for deriving drag exerted on trees were studied. Previous studies have stated that the drag coefficient of a cylinder is fairly constant when Reynolds number,R _e, is between 10³ and 10⁵ (e.g., Schlichting, 1979). This study clarified, however, that in cases of relatively dense arrangements of model trees (cylinders), the drag coefficient varies greatly with the density of the trees. As such, correlation between the drag coefficient and Reynolds number was found to be slight. Test results indicated that the drag coefficient of trees,C _d, correlates strongly with the coefficient of velocity,U′/U _* ′, friction factor of the channel bed,f′, and roughness concentration of trees × flow depth,aH′ or ratio of the area occupied by trees,λ. Furthermore, the drag coefficient,C _d, was also found to be slightly correlated with the gradient of the channel bed,I. Equations using either of the following parameters were obtained for deriving the drag coefficient,C _d, based on the experiment results:aH′; λ; U′/U _* ′; and Froude numberF _r. These equations allow fairly accurate calculation of drag exerted on trees.     

麦积山风景区的甘肃蛾类新记录

2006-2007年对麦积山风景区蛾类进行了集中采集,标本鉴定中,共发现14种蛾类为甘肃省首次记录,其中：灯蛾科3种,舟蛾科3种,尺蛾科、鹿蛾科各2种,夜蛾科、钩蛾科、燕蛾科、鞘蛾科各1种。     

辽宁首次发现兽类分布新记录—黄喉貂

2005年3月在辽宁朝阳小城子镇大营子村发现两只鼬科动物黄喉貂。经专家鉴定是辽宁省兽类分布的新记录,黄喉貂属濒危种类,已列入国家二级保护动物。建议保护好黄喉貂的野外生存环境,在其重要栖息地建立自然保护区,并建立人工饲养黄喉貂的基地,以增加黄喉貂的野外种群数量。     

江西忍冬科植物新纪录

报道5种江西新纪录的忍冬科植物,即二翅六道木Abelia macrotera (Graebn. et Buchw.) Rehd.、小叶六道木A. parvifolia Hemsl.、唐古特忍冬 Lonicera tangutica Maxim.、湖北荚蒾 Viburnum hupehense Rehd.、珊瑚树 V. odoratissimum Ker-Gawl.。     

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。     

江西九连山自然保护区蛇类新记录

2007年至2016年,作者通过对江西九连山国家级自然保护区蛇类的持续调查以及收集整理,发现九连山蛇类新记录3科7属,共8种.     

Silvopastoralism in New Zealand: review of effects of evergreen and deciduous trees on pasture dynamics

Complex interactions between livestock, trees and pasture occur in silvopastoral systems. Between trees and pasture, competition for soil resources (nutrients and water) occurs, becoming especially relevant when one of them is in scarce supply. Trees reduce light and water reaching the understorey layers according to tree density and canopy size. However, they may ameliorate extreme climatological features (reducing wind speed and evapotranspiration, and alleviating extreme temperatures), and improve soil properties, for example, deciduous tree litter may contribute to increased pH and soil nutrient concentrations. During tree establishment, there are generally negligible effects on pasture, irrespective of tree type. However, there is a decline in pasture production and nutritive value under shade with increasing tree age and higher stand density. Under the same conditions, deciduous trees affect pasture later (extinction point of pasture occurs at 85% of canopy closure) than evergreen trees (about 67% for Pinus radiata D. Don). This is mainly because deciduous trees have a leafless period that enables pasture recovery, and their litter smothers pasture less intensely because of its relatively fast decomposition. Silvopastoral studies conducted in New Zealand are reviewed to discuss these effects, and differences in the effects of evergreen and deciduous trees are shown using the examples of P. radiata, and Populus and Salix spp. respectively, which exist in many temperate countries. Future research needs are outlined.     

Coarse root growth of Veronese poplar trees varies with position on an erodible slope in New Zealand

Poplars are commonly planted on moist, unstable pastoral hill country to prevent or reduce soil erosion, thereby maintaining hillslope integrity and pasture production. Mechanical reinforcement by poplar root systems aids slope stabilisation, particularly when the roots are anchored into the fragipan or underlying rock. Total root length, mass and distribution of coarse roots (≥2 mm diameter) were determined for three Populus deltoides × nigra ‘Veronese’ trees in their 12th growing season after being planted as 3 m poles at upper slope (TU), mid-slope (TM) and lower slope (TL) positions on an erodible hillslope near Palmerston North in the southern North Island. Most of the roots were distributed in the top 40 cm of soil. Depth of penetration of vertical roots was dependent on slope position and limited by the available depth of the soil above a fragipan (0.35 m at the upper slope to 1.4 m at the lower slope). Roots penetrated the fragipan at the upper slope position where the soil depth was shallowest, and at the mid-slope, but not the lower slope position. Total coarse root length was 287.9 m for TU, 1,131.3 m for TM and 1,611.3 m for TL, and total coarse root dry mass (excluding root crown) was 8.15 kg for TU, 38.77 kg for TM and 81.35 kg for TL.     

Woody leguminous trees: New uses for sustainable development of drylands

Woody leguminous species are valuable crops because of their nutritional, economic, and ecological characteristics. Such crops have aided in the recovery of marginal lands for agricultural development due to their ability to fix nitrogen, control erosion, and act as a refuge for other species, in addition to their capacity to improve soil mineral composition and microbial biodiversity. Nevertheless, some leguminous trees are recognized to be one of the worst invasive species that affect negatively biodiversity and the entire ecosystem balance. In this study, we review new global uses for some woody leguminous crops, highlighting new nutraceutical and pharmacological properties, their uses as bioenergy sources, and their ecological uses for bioremediation opening new possibilities of management. We aim to bring knowledge on the multiple benefits that these woody plants continue to provide to humans from economic, social, and environmental standpoints.     

三种橡胶树乙烯利刺激剂对柑桔褐腐疫霉的毒力测定

通过含毒介质和橡胶叶片接种的试验方法,测定三种不同载体的乙烯利涂剂(含2％乙烯利)对柑桔褐腐疫霉的抑菌率,结果表明三种乙烯利涂剂均有不同程度的抑菌能力,其中抗病增胶灵抑菌能力最高,效能稳定,持效期长;而以淀粉和甲基纤维素为载体的涂剂抑菌能力较低,效能不稳定,持效期短。     

普洱市主城区行道树树种规划

通过对普洱市主城区道路树种的调查,在分析行道树现状的基础上,确定了体现南亚热带植物树种景观特色的经济技术指标,规划普洱市道路绿地基调树种9种,分别为：＊小叶榕（Ficus microcarpa）、＊云南樟（Cinnamomum glanduliferum）、假槟榔（Archontophoenix alexandrae）、＊灯台树（Comus controversa）、＊大花紫薇（Lagerstroemia speciosa）、＊冬樱花（Prunus majestica Koehne）、＊菠萝蜜（Artocarpus heterophyllus）、红花羊蹄甲（Bauhinia blakeana）、黄兰（Michelia champaca）。规划骨干树种共37种,其中常绿针叶树种3种,常绿阔叶树种14种,落叶阔叶树种3种,灌木10种,藤本7种（＊为乡土树种）。     

果树光合作用研究进展

综述了近年来国内外果树光合作用的研究进展。涉及的内容有：果树光合作用的基本特性;影响果树光合作用的内外因素;果树光合作用的测定方法,简述了叶绿素荧光动力学技术。