我省荣城县发现美国白蛾

美国白蛾 Hyphantria cunea(Drury)是一种世界性的危险性害虫。它能危害二百多种植物,包括林木、果树、农、作物、花卉和杂草等。     

马尾松尺■生活及生活习性的初步观察和防治试验

一、分布及危害马尾松尺 (Abraxax sp)是马尾松林的一个主要害虫。以幼虫期进行危害,症状似松毛虫危害状,严重时可将大面积的针叶吃光。其危害盛期,正是马尾松抽生长时期,所以对林木生长影响极大,连年受害可造成林木死亡。     

我国天牛虫灾的成因、现状与对策

天牛是我国危害最严重的林木害虫.虫灾的成因涉及天牛习性、环境条件和防治技术3个方面.目前的防治措施有一定的局限,对危害部位高和大面积防治还缺乏简便实用的措施.天牛研究方面有待解决的问题主要有:(1)混交林在天牛治理中的地位与控灾机制;(2)人工林经营模式;(3)天牛成虫的化学生态学;(4)林木对天牛的抗性机制.天牛虫灾的治理应坚持预防为主的方针,通过人工林栽培制度和经营模式变革,合理利用林木抗虫性,营造生态防虫林.进而研究出配套的虫害管理模式和林分经营模式,实现天牛虫灾可持续治理目标.     

对伊藤厚丝叶蜂生活史及习性的观察

伊藤厚丝叶蜂是我国近年才发现的一种新记录种的害虫,该蜂繁殖快、危害严重,目前在本溪县已有近0.2万hm2(3万亩)落叶松遭受不同程度的危害,从刚郁闭的幼林至50年以上的成林都受到不同程度的危害,严重的把整片林木的针叶全部食光。该蜂生活史及其习性尚不太清楚,查清其生物学特性,有一定的学术意义,也可为生物防治和预测预报提供科学依据。     

松针小卷蛾发生的环境及防治试验

松针小卷蛾(Epintia rubi ginosana)是近几年来危害幼严较为严重的一种隐蔽性害虫,对林木生长影响极大。从2005年开始,对这一害虫发生的环境和防治方法进行了比较系统的研究,提出了预防及防治措施。     

危害林木的几种铁线莲属植物初步研究

就铁线莲属Clematis植物对林木造成的危害情况进行初步研究和调查。结果表明:甘青铁线莲Clematis tangutica(Maxim.)Korsh、长花铁线莲C.rehderiana Craib和黄花铁线莲C.intricata Bunge对祁连园柏Juniperus przewalskii、青海云杉Picea crassifolia、沙棘Hippophae rhamnoides等植物的正常生长造成了一定危害和潜在影响,可造成林木长势衰弱,严重时导致林木死亡。3种铁线莲属植物在青海省天然林、人工林发生较为普遍,尤以甘青铁线莲分布最广、危害树种最多。     

松材线虫病发生及其检验技术的研究进展

松材线虫病是一种毁灭性的林木病害。该病在国内危害严重、扩散迅速，是重要的对内、对外检疫性林木病害。本文对松材线虫病发生、危害及当前的主要检验技术进行了介绍。     

注重森林生态系统的保护和改善综合治理马尾松毛虫

马尾松毛虫(Dendrolimus punctatus Walker)不仅危害马尾松,也危害湿地松,是我区最主要的食叶害虫。每年发生上万公顷,最严重的年份发生面积达3万公顷。对林木生长、松香生产损害较大,直接影响到湿地松种子园的产量和质量。     

栎冠潜蛾生物学特性及其防治的研究

前言栎冠潜蛾(Tischeria decidua Wocke)属鳞翅目(Lepidoptera)冠潜蛾科(Tischeriidae),是栓皮栎(Quercus variabillis BL.)叶部的一种主要害虫。由于它的危害,致使叶子干枯脱落,轻者影响生长,重者枯梢或整株枯死。1958年我场营造的栓皮栎林,均受不同程度的危害。由于林木是零星分布,加之对它的生物学特性了解     

林地鼠害的防护及补救措施

2002年秋冬季节，克拉玛依市绿化林木不同程度地遭到埂田鼠、红尾沙鼠、大尾沙鼠、灰仓鼠、圣柳沙鼠等10余种鼠类的危害，其对林木的危害方式主要是为了磨牙而啃咬树皮。林木平均受害率达到14％，严重的地区高达60％。鼠害对林地的危害非常严重，在秋冬季啃食林木的根和树皮，主要是对林木的根基部树皮进行环剥。为了能够有效消灭鼠害，     

Bark gnawing of forest trees by voles during the growing season

This study investigated the impact of small rodents on young trees during three growing seasons (2018–2020) in the Czech Republic. Tree damage by small rodents, the quantity and quality of herbaceous plant biomass and the species composition of small mammals were monitored at two sites in European beech forest plantations. The number of trees damaged during three growing seasons correlated positively with fibre content and negatively with nitrogen content in herbaceous plant biomass. The importance of winter precipitation is reflected in the positive correlation with nitrogen content in herbaceous plant biomass. The observed tree-gnawing damage correlated positively with the abundance of one rodent species only—the bank vole. The highest damage occurred after the concurrence of a dry winter and a higher number of voles. Given current climate variability, this situation could become more common in the future. Gnawing may be a limiting factor for the successful restoration of trees with thin bark—in our case, European beech. In addition, the proportion of this woody species should be increased to achieve a more stable and closer composition in the Czech Republic.

     

我国西北地区啮齿动物的发生现状与趋势研究

研究结果表明：西北各省区地下害鼠主要监测对象是甘肃鼢鼠、中华鼢鼠和高原鼢鼠;监测的主要地面害鼠是小家鼠、达乌尔黄鼠和灰仓鼠等13种;草兔已经成为一种危害农林牧业生产的主要灾害。害鼠发生面积不断扩大,且有爆发成灾的趋势。退耕还林工程的实施,使原先发生在农田的害鼠变成了林地害鼠,造成了在局部地区林地鼠害发生面积的急剧增加。     

Characteristics of tree damage by the grey red-backed vole (<Emphasis Type="Italic">Myodes rufocanus bedfordiae</Emphasis>) in a deciduous forest in Hokkaido,Japan

In deciduous forests, tree seeds and seedlings are frequently exposed to high predation by small rodents, and this predation can have an important effect on forest regeneration. However, damage to large trees by small rodents has not been studied, except for damage observed during timber production. To determine factors affecting damage to large trees by the grey red-backed vole (Myodes rufocanus bedfordiae), the characteristics and spatial patterns of tree damage by voles at vole wintering sites were examined over 3 years in a deciduous forest in Hokkaido. This study found that the location of damaged trees was related to vole wintering sites. Vole damage was affected by tree species. Damaged trees were heavily concentrated in small areas. Leaning trees and trees that had suffered previous damage were more likely to be damaged. However, the diameter at breast height was not significantly related to vole damage. These differences in susceptibility to vole damage may result in different tree mortality.     

Zur Abhängigkeit des Nagerbefalls vom HCN-Gehalt der Knollen von Manihot esculenta Crantz

Studies on rodents damage in relation to Cyanogenic Glucosides content in tubers of Manihot esculenta Crantz Rodents are the major pests of Cassava(Manihot esculenta) and inflict heavy losses in the field. In order to explore the possibilities of controlling rodents by developing resistant varieties in relation to HCN content studies were undertaken at Central Tuber Crops Research Institute, Trivandrum. In total 7 varieties were studied for extent of damage and tuber characters. The studies indicated that varieties, such as Ce 178, Ce 281 and Ce 96 having minimum concentration of HCN in rind were highly susceptible to rodent attack and were preferred over varieties, such as Ce 432 and Ce ll9, having higher concentration of HCN in the rind. Thus there is ample scope for evolving a cassava variety with higher concentration of cyanogenic glucosides in the rind and negligible quantities in the flesh to ward off heavy rodent attack, in the field.     

Damage to Brazil nut trees (Bertholletia excelsa) during selective timber harvesting in Northern Bolivia

The success of multiple forest management systems is contingent on a variety of social, economic, biophysical, and institutional factors, including the integration of timber and non-timber forest product (NTFP) extraction and management. Selective logging for timber is increasingly taking place in forests where the collection of Brazil nuts, a high-value Amazonian NTFP, also occurs. We report on logging damage to Brazil nut trees in three certified timber concessions in Northern Bolivia from which timber is harvested using reduced-impact logging (RIL) guidelines and nuts are gathered yearly from the ground by local people. Observed frequencies of logging damage to Brazil nut trees were low, likely mirroring the low intensity of timber harvesting (∼0.5 trees/ha and ∼5 m³/ha) being currently applied across the study area. Of the trees ≥10 cm in diameter at breast height about 0.1 Brazil nut trees and 0.4 timber species per hectare suffered some degree of logging damage. Crown loss was the predominant damage type for Brazil nut trees accounting for 50% of all damage. In spite of the observed low rates of tree damage, we further recommend that RIL guidelines be amended to include the pre-harvest marking of pre-reproductive Brazil nut trees along with the future crop trees of commercial timber species. Further refining directional felling to reduce crown damage to Brazil nut trees would also serve to help maintain nut yields in the long term.     

Snow damages on trees of an uneven age in mixed broadleaf forests:effects of topographical conditions and tree characteristics

Snow damage on natural stands is an important problem concerning mountainous forest management.In the present research,the frequency and intensity of heavy snow damage on natural stands and the relationship of damages with characteristics of trees,stand and topography were studied in mountainous forests of northern Iran.A systematic sampling design was applied to the study area(140 ha),with 122 circular plots.The grid dimension was100 m and each plot area was 1000 m^2.The four types of snow damage to trees include:crown damage(8.6%),stem breakage(5.4%),uprooting(3.2%),and bending(1.4%).The frequency of crown damage grew with an increase inthe diameter at breast height(DBH),while the frequency of stem breakage,uprooting and bending decreased with an increase the DBH.The frequency of crown damage,stem breakage,and total damages was related to tree species(p<0.01).Not all tree species were equally susceptible to snow damage.The amount of damage grew with increasing elevation and slope angle and decreased with increasing soil depth.Young trees(DBH<25 cm)were more susceptible to snow damage than other trees.Snow damage decreased by as the trees in the stand became more mixed in age.The susceptibility of trees to snow damage increased by height and slenderness coefficient.With adequate silvicultural operation,snow damage can be reduced to a minimum level in these natural forests.     

华北地区经济树种蚧害研究

对华北地区经济树种蚧虫的种类区系、发生和分布规律及为害特点进行了系统研究。据调查，现已知华北经济树种蚧虫共有９科１２２种。随纬度增高、立地条件恶化、植物群落简单、人为活动频繁、管理水平粗放，蚧虫种类增多，为害严重。一般情况下，观赏树木受害普遍，温室植物受害严重，果树及平原地区林木部分受害，山地森林受害轻微。     

人工林鼠害防治指标补充研究

通过主害期对目标鼠种和危害率的相关关系研究,提出了杉木、柳杉和油松的防治指标。在不同林龄分别是：１年～３年时目标鼠种鼠密度为１．７０、２．４０和１．７４;４年～６年时为０．９４、１．３和０．６２。     

湟源县退耕还林区鼠害发生危害及防治技术分析

本文从湟源县退耕地害鼠种类、危害程度及防治现状入手,分析了湟源县退耕地鼠害发生的主要原因,提出了适于当地退耕地鼠害防治的综合措施,为退耕地鼠害防治提供了技术依据。     

Growing situation of afforested trees and damage to lower-story trees caused by felling in multi-storied forest management in Peninsular Malaysia

The growing condition of afforestation trees and damage to lower-story trees caused by felling and hauling of upper-story trees in a multi-storied forest in Peninsular Malaysia was surveyed. Seventy months have passed since the planting ofAcacia mangium upperstory trees, which have grown 233 m³/ha in volume. The growth ofShorea leprosula thirty-five months after planting of lower-story trees have reached 5.54 m in height. However, as the ratio of height to basal diameter exceeds 100:1, trees are tapering to a considerable degree. A backhoe was installed in order to fell the upper-story trees. From the results of logging, the damage ratio estimation of the lower-story trees was simulated by using the Monte Carlo method. The damage ratio differed considerably depending on planting patterns, height of upper-story trees and felling skills. The results of this survey proved that the felling and hauling of upper-story trees would be technically feasible in the future, except when one row upper-story trees and one row lower-story trees method were employed.