城市行道树生长衰弱原因探析及对策

本文从道路拓宽改造、临街门市人为损坏、融雪剂影响以及病虫危害等四个方面分析了城市行道树生长衰弱的原因,提出了要从规划设计、加强对临街商铺和道路改造施工队伍管理、树势复壮、降低融雪剂危害和病虫害防治角度改善行道树生长环境,促进城市行道树良好生长,发挥其应有的生态功能。     

绿化带大树主要病虫害调查分析

通过对丹东市主要绿化树种病虫害的调查分析,结果表明:危害行道树和绿化带的病虫害很多,病害主要是流脂病、腐烂病、干腐病和黑斑病,其中流脂病和腐烂病发生的面积大,发病率较高;高温、高湿和栽植过密是导致病虫危害的主要因素;混交度较差,纯林比例大,给病虫害传播创造了条件;生长势较弱的区段病虫危害相对较重。     

云杉八齿小蠹的风险分析

云杉八齿小蠹(Ips typographus)分布范围广,可危害多种健康和衰弱的云杉(Picea asperata)和松属树种。幼虫危害初期在树干坑道内取食,植株生长正常;危害中期被害树干上可见小蠹羽化孔,树皮较易剥离,针叶变色;严重危害时树皮极易剥落。由于其适应性强,危害存在隐蔽性,该虫对我国北方针叶林造成重大经济危害。通过对云杉八齿小蠹的风险分析,其风险评估值R=1.85,在我国属中度危险的林业有害生物。     

包头市区道路绿化树种结构及应用

近年来,包头市绿化事业取得飞速发展,城市绿化覆盖率由1990年的24.2%提高到目前的34.4%。但是,由于树龄、树种结构等原因,树木病虫害较重,特别是"天牛"危害严重,直接影响了包头市绿化成果。因此,要根据现有行道树生长结构存在的问题,科学选择、配置行道树种,以提高包头市区道路绿化水平。包头市区现有道路80多条,常绿乔木主要有油松、樟子松、桧柏、云杉、杜     

美杨播种育苗成绩良好——苗高140—190厘米,地径0.5—1.2厘米

美杨(Populus Pyramidalis)树干通直,生长迅速,是砂区造林和行道树的优良树种。过去美杨都用插条繁殖苗木,造林后有早期衰老、树干腐心的缺点,而且容易生病虫害。实践证明:实生苗造林可以克服这些缺点。今年     

施用有机液态肥对城市行道树土壤肥力的影响

城市行道树土壤营养面积小、普遍板结、盐碱化严重、污染较重、肥力底下。通过多次对行道树灌施有机液态肥,可改良行道树土壤,提高肥力、含水量,改善质地,降低pH值,促进行道树健康稳定生长。     

小木蠹蛾雄蛾对雌蛾性信息素提取物及合成标准化合物的电生理反应

小木蠹蛾 (ＨｏｌｃｏｃｅｒｕｓｉｎｓｕｌａｒｉｓＳｔａｕｄｉｎｇｅｒ)是北京、天津等地园林树木白蜡、国槐、丁香、银杏、海棠等主要蛀干害虫 ,据 1 979年对北京市行道树的调查 (高瑞桐等 ,1 983;蒋三登等 ,1 983) ,遭此虫危害严重的地方被害株率高达 80 %以上。 1 998年再次调查发现 ,虫害程度有增无减 ,在一根长 50ｃｍ、直径8ｃｍ白蜡树段内幼虫达 2 63头。受害树株常发生风折、枯枝甚至整株死亡。同时幼虫从树干内排出粪屑挂满树枝树干或飘落地上 ,有碍市容卫生。防治方法主要是修除被害树干和施用化学药剂 ,长期使用这些方法不仅…     

浅谈吴江地区行道树养护管理技术

指出了行道树相比其他绿地，生长环境条件较差、长势弱，且易发生病虫害，因此提高现有行道树的养护水平尤为重要。依据多年绿化养护工作实践，对行道树养护管理中施工因素、修剪和病虫害防治三方面的要点进行了探讨。     

行道树树种结构及健康评价的研究

采用实地观测方法,研究了长春市主城区(环城路内)78条主要道路行道树的树种结构特征与健康状况,结果表明:垂柳、新疆杨和糖槭是研究区内行道树的主要树种,分别占研究区树木总株数5 897株的12.79%、10.99%和10.53%;平均密度为276株·hm-2,平均胸径、平均树高、平均活枝下高和平均冠幅分别为11.7 cm、742 cm、201 cm和347 cm。环城路以内行道树43.96%的植株处于亚健康等级;健康和不健康植株分别占17.49%和10.99%;中等健康植株占27.66%。     

鹅掌楸与元宝枫的培育

鹅掌楸 鹅掌楸又名马褂木,落叶乔木。树干端直高大,生长迅速,材质优良,寿命长,适应性广,叶形奇特,少病虫害,是优美的}H冈和行道树绿化树种,也是良好的用材树种．具有一定的耐寒性,能耐-15℃的低温。根系发达,不耐水湿,也不耐干旱。     

北京城区银杏行道树生长现状与健康状况研究

The planting site, size, and health condition of street tree Ginkgo biloba in Beijing urban area were investigated and the influence factors were analyzed based on filed survey. The results showed that G. biloba were mainly planted in tree pit within strip planting median. The average height, diameter at breast height and canopy diameter were 8.11 m, 13.22 cm and 4.07 m, respectively, 82.9% trees were less than 10 m in height, and most G. biloba trees were still in the initial stage of height and diameter increment. The tree health status was described with three classes: class I (healthy), class II (fair) and class III (unhealthy). The percentage of class I, II and III for G. biloba trees in Beijing urban area accounted for 16.0%, 37.2% and 42.9% respectively. The results of analysis showed that the health status of G. biloba was associated with the site condition, tree size and management practices. The trees planted in urban forest patch grew better than the trees planted in green belts and tree pits; meanwhile, the bigger trees were healthier than the smaller ones. In addition, the effects of urban heterogeneous environment and human activities on the health of Ginkgo biloba were analyzed and the suggestions on management were launched.     

Effects of bark stripping by sika deer, Cervus nippon, on wind damage to coniferous trees in subalpine forest of central Japan

We evaluated the effect of bark stripping by sika deer (Cervus nippon), and subsequent wood decay, on tree fall in a coniferous forest on Mt Ohdaigahara in central Japan from July to September 2006. This valuable primeval coniferous forest is declining because of bark stripping. Broken trunks of Abies homolepis and Picea jezoensis var. hondoensis had more serious decay and larger bark-stripping wounds on the trunk than standing trees, suggesting that bark stripping causes trunk decay and results in broken trunks and uprooting by typhoons.     

寄主树木、寄主和环境因子对松褐天牛深沟茧蜂寄生率的影响研究

[目的]松材线虫病是我国对森林危害和威胁最严重的病害,控制其传播媒介昆虫松褐天牛是防治松材线虫病的主要手段。作者发现的松褐天牛深沟茧蜂(Iphiaulax monochamusi Yang)是寄生松褐天牛中老龄幼虫的重要天敌。为明确松褐天牛深沟茧蜂的寄生率与寄主树木、寄主和环境因子的关系,开展了本研究。[方法]通过解剖46株松褐天牛危害致死的马尾松,调查了松褐天牛深沟茧蜂寄生率与马尾松、松褐天牛和环境因子之间的关系。[结果]调查研究表明:寄主树木的高度、胸径和树龄对松褐天牛深沟茧蜂寄生率没有显著影响,松褐天牛的数量对松褐天牛深沟茧蜂寄生率亦没有显著影响,而松褐天牛幼虫龄期和松褐天牛幼虫在树干上的位置显著影响松褐天牛深沟茧蜂寄生率。松褐天牛深沟茧蜂寄生率与松褐天牛龄期呈显著正相关,其偏好寄生3~5龄幼虫;就天牛在其危害寄主树木上的位置而言,松褐天牛深沟茧蜂偏好寄生马尾松主干上部和在韧皮部危害的松褐天牛幼虫,其对位于马尾松树干上部的寄主幼虫寄生率最高,达27.38%,对在韧皮部生活、危害的寄主幼虫寄生率为20.18%,显著高于位于木质部生活的寄主幼虫寄生率(5.46%)。逐步回归分析表明:影响松褐天牛深沟茧蜂寄生率的关键环境因子是寄主树木的坡位和其它天敌寄生率,其中,坡位与松褐天牛深沟茧蜂呈显著正相关,其它天敌寄生率与松褐天牛深沟茧蜂寄生率呈显著负相关。[结论]以上研究初步明确了松褐天牛深沟茧蜂的寄生率与寄主树木、寄主害虫和天敌之间的关系,为今后利用该重要天敌控制松褐天牛打下了基础。     

Rapid living crown reduction caused by Gremmeniella abietina affects foliar nutrient concentrations of Scots pine

The foliar chemistry of diseased and healthy trees was studied one growing season after severe reduction in living crown caused by Gremmeniella abietina in four young Scots pine (Pinus sylvestris) stands. Sample trees were chosen pairwise on the basis of the living crown length: a diseased tree with about 50% live crown reduction and a healthy tree in each pair. Fifteen elements were determined in the youngest healthy needles on the lateral top shoots of each sample tree. Diseased trees had higher foliar boron, manganese and sodium concentrations and lower magnesium, iron, zinc, copper, potassium, nitrogen and sulphur concentrations compared to the healthy trees. Foliar calcium, aluminium, phosphorus, carbon and hydrogen concentrations did not differ between the diseased and healthy trees, except for P and A1 in two of the stands when the stands were analysed separately. Significant correlations between the needle element concentrations and crown ratio (length of the living crown/tree height) were found especially for B (increasing B with decreasing crown ratio) and for Mg, Fe and Zn (decreasing concentrations with decreasing crown ratio). The effect of G. abietina-induced living crown reduction on tree nutrient status and the role of these mineral nutrients in the susceptibility are discussed.     

汉寿县行道树研究

行道树是城市绿地系统的骨架和网络,作为城市森林系统具有连续性的主要构成因素,能够直观反映城市风貌。就汉寿县行道树现状,总结出树种单一、季相变化树种使用过少,对速生树种与慢生树种相结合的原则应用力度不够,人为破坏严重等方面的问题,并提出了相应意见和建议,为以后在行道树方面作研究参考。     

Effects of azadirachtin injection in litchi trees (Litchi chinensis Sonn.) on the litchi stink bug (Tessaratoma papillosa Drury) in northern Thailand

The litchi stink bug (Tessaratoma papillosa Drury) is one of the major pests of litchi (Litchi chinensis Sonn.) in tropical Asia. Systemic effects of azadirachtin (at a concentration of 0.17 g active ingredient per centimeter trunk diameter) on T. papillosa were examined by injecting the dissolved product (NeemAzal U) into the trunks of four caged litchi trees in an orchard in northern Thailand. Four untreated caged trees served as control. Mean weekly mortality rates of individuals released on the treatment date (initially 55 nymphs per cage) were significantly higher in the treatment cages (55%) than in the control cages (10%) between the second and the fourth week of the experiment. Mortality in the treatment cages was probably due to both toxic effects (ecdysis inhibition) and antifeedant effects (starvation). Weekly mortality rates of individuals released 2 weeks after tree injection (initially 20 nymphs per cage) were not significantly different between treatment and control cages, indicating a weakening effect of azadirachtin, 2–3 weeks after tree injection. Azadirachtin concentration in ripe fruits was less than 5 mg/kg fruit pulp 18 days after tree injection. Although the results of this study are not yet sufficient for practical recommendations, they provide indications of alternative options for integrated pest management approaches. The azadirachtin tree injection method should also be tested against other pests of litchi, and of fruit trees in general.     

Millet production under pruned tree crowns in a parkland system in Burkina Faso

As a tree management tool, three treatments of crown pruning (total-pruning, half-pruning and no-pruning) were applied to Vitellaria paradoxa (karité) and Parkia biglobosa (néré) in agroforestry parkland systems in Burkina Faso. The area under each tree was divided into four concentric tree influence zones (Zones A: up to 2 m from the tree trunk, B: up to half of the radius of the tree crown, C: up to the edge of the tree crown and D: up to 2 m away from the edge of the tree crown). Millet production under these zones and outside was assessed during two cropping seasons over the study period of three years and the results showed that tree crown pruning had significant effect on millet production and the highest millet grain yield and total dry matter were produced under total-pruned trees (507 ± 49 and 2033 ± 236 kg ha⁻¹ year⁻¹, respectively). Light transmission, transpiration and soil nutrient status under the trees were also analysed in relation to millet production. The results of the analysis showed that total-pruned trees gave the highest millet production due to the reduction by crown pruning of the effects of large tree crowns on PAR transmission below crowns and rates of transpiration by trees. Soil was more fertile closer to the tree trunks than outside tree crowns. This may also be one of the reasons why millet overall performed better under Zone B than outside tree crowns. The higher production of millet under Zone B than under Zone A, the zone closer to the tree trunk, may be due to lower light intensity and more intense competition for water between trees and crops under Zone A. It was concluded that at least in the short term millet production could be improved by crown pruning of both karité and néré, but long term effects may depend on the ability of the trees to maintain the amelioration of soil fertility and on how quickly the trees recover from pruning. This revised version was published online in June 2006 with corrections to the Cover Date.     

On-farm evaluation of the establishment of clonal rubber in multistrata agroforests in Jambi,Indonesia

Perennial tree crops are often grown in complex multistrata systems that incorporate natural vegetation. These systems contribute simultaneously to sustaining rural livelihoods and to the conservation of biodiversity, but their productivity is usually low. Introduction of high yielding germplasm, usually selected in monocultural plantations, is a potential way to increase productivity, but a critical requirement is that such plants can be established in a competitive multispecies environment. The establishment of clonal planting stock in the jungle rubber agroforests of Indonesia was explored through participatory on-farm research. The trial involved four farmers who grew clonal rubber trees in a total of 20 plots, constituting five replicate experimental blocks spread across four farms. Unexpectedly, vertebrate pest damage by monkeys (Presbytis melalophos nobilis) and wild pigs (Sus scrofa) was the most important influence on establishment, explaining almost 70% of the variation in rubber tree growth. The amount of labour invested in weeding was also positively correlated with rubber tree growth. Farmers generally decided to completely cut back vegetation between rows of rubber trees, including potentially valuable trees, rather than weeding within the rows and selectively pruning trees in the inter-row. Farmers thought that the inter-row vegetation would harbour vertebrate pests and compete with the clonal rubber, and they had access to fruits, firewood and other non-timber forest products from other land. Thus, contrary to expectations, when offered clonal germplasm, farmers opted to use plantation monoculture methods to protect what they considered a valuable asset, rather than maintain the traditional multispecies strategy they use with local germplasm. This revised version was published online in June 2006 with corrections to the Cover Date.     

浅析广州市行道树引起的交通安全隐患及防范措施

由于多种原因,时有行道树倒伏压车、影响交通或折枝伤人等事故的发生。该文从茂密树冠造成视觉盲区,滥用大苗,树穴与花基设计不周;管理养护中修剪不当,浇灌不合理,病虫害防治不力;该文还从树穴土壤质量差或地下水位高,地面铺装不透水不透气,人为损坏严重及树体衰老等多个方面,探讨了行道树引起交通安全隐患的原因。并从技术和管理两个方面提出了相应的防范措施：在视距三角形范围内采用通透式配置,慎用大树,改地适树;采用透水透气铺装,加强管理和养护,加强衰老树木的管养和复壮;加强行道树的巡查处理,降低人为损坏的影响等。     

Post-fire attractiveness of maritime pines (<Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait.) to xylophagous insects

The spectrum and dynamics of xylophagous insects infesting Pinus pinaster after a fire event were studied from November 2007 to December 2008 at Sierra de Outes (Galicia, NW Spain). Insects were collected within and outside the fire area. Relationships among species status, species abundance, tree parameters and tree injury were assessed. Mortality of injured trees was also recorded. Insect colonization built up consistently during the first year after the fire, although the pests did not colonize unburned trees in nearby areas. Thirteen insect species from six xylophagous families were collected. Tomicus spp., Buprestis novenmaculata, Anobium punctatum and Pissodes castaneus were the first species detected. Tomicus spp. (29%) and Ips sexdentatus (23%) were the dominant taxa. Bole char height and soil burn severity were positively correlated with insect presence. Trees with short stem diameter and thinner bark were also preferred. B. novenmaculata presence was positively correlated with crown scorch. Loss of cambium hydration was negatively related to the occurrence of pests, likely because sapwood desiccation and loss of nutrient impede brood development. About 33.3% of the fire-scorched pines died. The results recommend the removal of injured and dying pines after fire, to avoid the rise of pest population threatening recovering trees in the burned areas.