Soil Properties Affecting the Frost Sensitivity of Beech Bark in Southern Sweden

Decline in pH and leakage of base cations have been recorded in beech forest soils in southern Sweden. This study investigated the influence of soil properties on frost sensitivity in beech bark and evaluated the effects on frost sensitivity of soil treatment with lime, wood ash or excessive N fertilization. Beech trees on five experimental sites were studied. The results indicated that beech trees subjected to a comparatively low C/N ratio and low concentration of nutrient elements in the mineral soil layer were predisposed to a higher sensitivity to frost. Seven years after treatment, no effects of N fertilization were detectable in the soil, but positive effects of liming were recorded. There were no obvious effects of bark ash amendments, owing to large differences among blocks at the site.     

树木剥皮再生研究综述

本文介绍了树木剥皮再生研究的概况,包括树皮再生的组织学、剥皮再生过程中树木的生理反应、再生皮和原生皮有效成分比较以及剥皮再生的技术措施等;并提出了皮类树木剥皮再生研究发展的方向。     

Some Aspects of the Growth and Spread of Fire in the Open

This paper describes some recent experimental and theoreticalwork on the growth and spread of fire in the open and discussessome examples of field data in terms of the theoretical calculationspresented. The lengths of flames from laboratory fires have been relatedto the size and rate of burning of the fuel by formulae derivedfrom a simplified dimensional analysis. The effects of a windblowing across a long fuel bed on the length and orientationof flames are also described. The scaling laws for flame heightsuggest that in the horizontal spread of fire, heat transferfrom the flames above the fuel bed is important primarily withshallow fuel beds. It is suggested that the main effect of a wind on crib firesis aerodynamic. The wind deflects the advancing fire front fromthe vertical, but perpendicular to this deflected front therate of spread of fire, at least for cribs, is roughly the sameas in still air. However, a theory of spread allowing for heattransfer through the fuel bed and radiation from the flamespredicts that there can be a stable ‘fast‘ spreadas well as a ‘slow’ spread. In ‘fast’spread the flames are thick and control the spread. In ‘slow’ spread radiant heat transfer from theburning zone is usually responsible for the spread. The flamesare thin and of low emissivity. The most important factors determiningthe rate of ‘slow’ spread R are ^pb the bulk densityof the fuel bed and ø the deflection from the verticalof the front of burning fuel which varies with wind speed. Rpb cos ø is approximately constant over a wide rangeof conditions with an order of magnitude of 5–10 mg cm^–2s^–1.     

珍稀树种山毛榉人工培育生长调查分析

通过对旺苍县国营林场2006年营造的山毛榉林在不同土壤厚度、坡向条件下的生长状况的调查分析,比较山毛榉在不同条件下的生长状况的差异,为人工培育山毛榉提出参考。     

杜仲树皮的采剥与加工

通过杜仲树皮的采剥与加工试验和实践,在做好杜仲树皮采剥的基础上,采用科学的采剥技术,剥皮后养护和烂皮病的防治,以及杜仲树皮的加工等技术措施,采剥效果好。     

3种壳斗科树种苗木物候及其生长规律研究

对壳斗科的大叶青冈、小叶青冈、榄叶石栎的种子采集、处理，种子千粒重，优良度及育苗方法进行了观测试验，对其苗木物侯、根系生长及苗高生长规律进行了初步研究。     

树木抗病的生理生化学研究进展

对树木受病原物侵染前后体内生化物质及其变化状况和诱发产生的多种生理生化代谢差异在寄主抗病性中作用的研究现状进行了概述，指出，目前关于树木抗病性的研究多集中在相关因素的比较分析上，有关抗病的分子机制和抗病基因定位等研究是今后深入探讨的重要方面。     

药剂防治橡胶树外褐型死皮病试验

三种药物防治橡胶树割线外褐型死皮病3年的试验结果:B药物防效最好,防效为69.5%和70.4%,干胶净增产率5.2%;其次为“保-01”,防效为49.9%和43.8%,干胶净增产率9.1%;最差为A药物,防效为3.5%和26.8%,干胶净增产率0.1%,     

森林土壤研究几个方面的进展

文章从森林土壤组成，结构与功能一致性这个原理出发，论述了森林土壤物理性质，化学性质，生物化学活性以及森林土壤微生物等方面的研究进展，阐述了人类在有限的，可供利用的土地上维护和提高森林土壤生产力的途径。     

Some Aspects of the Relationships between Growth Vigour, Canker, and Dieback of European Larch

From the detailed sampling of two European larch provenancetrials in Scotland, an increase in canker coincident with outbreaksof epidemic dieback was demonstrated. There was generally lesscankering on unthrifty trees although this was not correlatedwith the severity of dieback. There was a general positive correlationbetween growth vigour, as measured by mean annual radial increment,and incidence of canker healing, and it was shown that cankersare initiated on stems of all ages. Although there was no overallstatistical correlation between growth vigour and subsequentseverity of dying back, the most unthrifty trees were considerablyless affected than the most vigorous. An increase in suitablecanker infection courts as a result of dieback is suggested,and the possible roles of climatic factors, Adelges spp. andviruses in the dieback syndrome compared. It was concluded thatvirus transmission by Adelgids merits further investigation.     

落叶松母树林病虫害调查初探

落叶松母树林又叫采种种子林 ,它的主要任务是生产品质优良的林木种子。但是由于种实害虫的危害 ,严重影响种子的收成 ,甚至颗粒不收。为此 ,我们对吕梁山森林经营局所属的上庄种子园 4 6 .6 7hm2 华北落叶松母树林进行了全面调查 ,为该母树林病虫害的监测与控制提供了可靠的依据。按照常规方法 ,在踏查的基础上进行标准地调查 ,选取标准地 0 .0 7hm2 ,随机抽取 5 0株母树进行每木调查 ,现将调查结果报告如下 :1　母树林地自然概况1.1　地理概况　　上庄种子园位于吕梁山脉南部紫荆山东麓。东经111°12′,北纬 36°4 5′,海拔 15 80 m～ 193…     

抚育间伐对林木生长及其稳定性的影响

不论是在人工林还是天然林管理中,抚育间伐都是一种极为常见的育林手段,在林木生长过程中具有非常重要的作用.大量实践证明,抚育间伐不仅能提高林木生长质量还有利于生态环境的改善.基于此,立足抚育间伐概念解析,分析了抚育间伐对柳杉生长和稳定性的影响,阐述了现阶段我国抚育间伐存在的问题,并提出了抚育间伐建议,以期能够为林木经营提...     

板栗膏药病对树皮电阻值的影响

为给板栗膏药病的防治和进一步研究提供参考,对安徽省舒城县河棚板栗产区板栗膏药病与树皮电阻值的相关性进行了研究,结果表明:树皮电阻值与病情呈显著的正相关,即感病程度越重树皮电阻值越大,感病越轻电阻值越小;同一植株上同一病斑的不同位置,树皮电阻值差异极显著,即病斑中央树皮电阻值最大,高于病斑上方、病斑下方、病斑侧面和健康处。     

土壤水分对杜仲剥皮再生的影响

分别对12和25年生杜仲进行Ⅰ、Ⅱ、Ⅲ、Ⅳ级供水处理,研究不同水分条件对杜仲愈伤组织和再生皮生长的影响.结果表明:供水改善了林地水分条件,土壤平均含水量和贮水量增大,25年生杜仲消耗土壤水分较多,土壤含水量较12年生杜仲林地的低.杜仲剥皮后,供水能加快愈伤组织的形成,剥皮后第5 d,处理Ⅰ、Ⅱ、Ⅲ均有微绿色的愈伤组织出现,较对照提前5 d左右;剥皮后25 d,12和25年生的愈伤组织厚度分别达到1.00和0.94mm,生长速度分别为0.040和0.037 mm·d-1,分别较对照增加47.1%和80.8%.供水能显著促进杜仲再生皮的生长,剥皮后5个月,12和25年生杜仲Ⅰ、Ⅱ、Ⅲ、Ⅳ级供水处理的再生皮厚度分别较对照增加5.0%、22.5%、75.8%、71.7%和18.5%、29.3%、80.7%、95.0%.6月份是杜仲再生皮生长的关键期,供水对再生皮生长最有利.杜仲水分利用效率在Ⅲ级供水处理时最大,12和25年生分别较对照提高39.3%和37.4%.生长季中,土壤含水量应保持在160～170 g·kg-1.     

Studies on the Health of Beech Trees in Surrey, England: Relationship between Winter Canopy Assessment by Roloff's Method and Twig Analysis

Trees and saplings of all sizes (total 229) were studied atthree amenity sites in Surrey representing mixed woodland, beechhigh forest and open parkland. Roloff's winter assessment ofthe twig pattern of growth demonstrated an underlying differencebetween the sites, which was consistent with an associationbetween greater deterioration and more exposure to climate extremesand pollutants. Trees showed deterioration with age but prematureageing was seen in 35–50-year-old parkland trees. Withinthe woodland the more exposed trees had worse scores. Quantitative twig analysis was carried out on twigs from theupper canopy of 19 trees and saplings. In the most severelysuppressed trees yearly growth declined from the 1976 drought.Subsidiary shoot development was markedly reduced in such treesand there were high numbers of distorted and acute angled shoots.The latter two characteristics increased with age with younghealthy trees having very few of these types of shoots, buttwo 35-year-old trees in open parkland showed premature ageingwith larger numbers of such shoots. Twig analysis defined categories of twig pattern according toage and deterioration levels. There was generally good correlationbetween these categories and the Roloff twig canopy score beforeanalysis or with canopy scores of similar sized neighbours.Objective criteria suggested for future studies were: (1) measurementof annual primary shoot growth; (2) total secondary shoot lengthrelative to a standard primary shoot length; (3) mean numberof subsidiary shoots per year; and (4) proportion of shootsgrowing at 40° or less.     

施肥对麻栎幼树生长发育的影响

采用正交试验设计法,通过施用尿素、过磷酸钙、氯化钾3类肥料对麻栎生长发育的影响作了试验分析。结果表明尿素是影响麻栎高、径生长的主要因素,其次是过磷酸钙和氯化钾;株施50g尿素对麻栎地径生长效果明显,与对照相比达到显著水平;麻栎幼树综合施肥,N、P_2O_5、K_2O施肥比例以2.5:5:1效果较好,与对照相比高、径生长分别提高56.20%和46.72%。     

柿树病虫害的防治措施

1　龟蜡蚧危害柿、枣、苹果、梨等果树生活史及危害症状　该虫 1年发生 1代 ,树上产卵树上危害 ,以授精雌成虫在树枝树干上越冬。次年 3月～ 4月开始活动吸食 ,5月底至 6月初发育成熟 ,卵产在母壳下面 ,每雌产卵 2 0 0 0粒左右 ,6月下旬孵出若虫在树枝或叶上危害 ,能随风传播。 7月份 3龄初期雌虫分化 ,形成龟甲蜡壳 ;8月下旬到 9月初为雄虫集中发生期 ,雄虫交尾后死亡 ,雌虫继续危害 ,并从叶上转到枝条上越冬。防治方法　落叶至发芽前 :1喷柴油乳剂 ,喷后半小时用木棒敲打树枝树干 ,使虫体遇震落地而死 ;2戴上手套或拿麻袋片捋掉树枝树干上…     

夏季树木病虫害防治的几点建议

随着经济的发展和城市建设规模的不断扩大,城市的生态环境有了很大的改善。但园林树木病虫害也随之发生,且极为普遍。盛夏是园林树木各种害虫、病原物等活动高发期,针对树木遭受病虫害不同程度危害的现状,提出几点防治建议。     

林木遗传改良发展中的新见解

本文针对我国林木育种界中存在的问题,重点介绍了国际上已通过试验验证了的一些新见解。这些新学术见解正推动着世界林木遗传改良沿高效、低成本和快速的方向发展,对正处在发展中的我国林木育种事业有重要借鉴意义。合理吸收和利用它们将有助于使我国林木遗传改良向低成本和高速方向发展,以缩小与世界水平的差距。     

温度对树木生长与木材形成影响的研究进展

对国内外有关温度影响树木生长与木材形成的研究现状进行了总结。影响树木生长及木材形成的诸多气候因子中，温度最重要，尤其是在干旱、半干旱地区或高纬度地区。近年来，有关树木生长与木材形成和温度变化关系的研究越来越引起人们的关注，并取得了较大的进展。最后对这一研究领域进行了展望。