Behavior of wood basic density according to environmental variablesOA

The relationships between climate conditions and wood density in tropical forests are still poorly understood.To quantify spatial dependence of wood density in the state of Minas Gerais(MG,Brazil),map spatial distribution of density,and correlate density with climate variables,we extracted data from the Forest Inventory of Minas Gerais for 1988 trees scaled throughout the territory and measured wood density of discs removed from the trees.Environmental variables were extracted from the database ...     

Aspects of forest restoration and hydrology:the hydrological function of litterOA

Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This study relates litter levels to water holding capacity and effective water retention among forest fragments under different passive restoration stages:46,11,and 8 years to better understand litter hydrological functions in the Cerrado.Water retention c apacity and effective water reten...     

Adaptation of pine wood nematode,Bursaphelenchus xylophilus,early in its interaction with two Pinus species that differ in resistanceOA

Pine wilt disease(PWD) is one of the most devastating diseases of Pinu s spp. and is caused by the pine wood nematode(PWN), Bursaphelenchus xylophilus(Steiner & Buhrer) Nickle. To study adaptation of PWN to survive in hosts that differ in resistance, we examined the self-regulatory characteristics of PWN at the biological and molecular levels early in the interaction. Two-year-old susceptible Pinus thunbergii and resistant Pinus taeda were selected for this experiment, and changes in PWNs af...     

Volatile metabolites of willows determining host discrimination by adult Plagiodera versicoloraOA

Plagiodera versicolora Laicharting is a highly damaging leaf beetle foraging on willow leaves.In willow germplasm collections,observation has shown that Salix suchowensis Cheng was severely foraged by this leaf beetle while Salix triandra L.was damage free or only slightly damaged.Results of olfactometer bio as says show that the headspace volatiles from leaves of S.triandra significantly repelled adult beetles,suggesting that this species produces volatile repellents against P.versicolora.S.suc...     

Retention of eucalyptus harvest residues reduces soil compaction caused by deep subsoilingOA

Eucalyptus harvesting,forwarding and soil tillage operations are among the main causes for compaction of forest soils,with potential impacts on productivity.This concern is especially important in areas with soils that are naturally compacted(fragipans and duripans).In these soils,tillage operations include the use of subsoilers that can reach depths of more than one meter and require heavy tractors that exert high pressure on the soil.One of the ways to try to minimize the effect of this compac...     

Molecular characterization and functional analysis of daf-8 in the pinewood nematode,Bursaphelenchus xylophilusOA

Bursaphelenchus xylophilus,causal agent of pine wilt disease,causes extensive damage worldwide.Strategies are needed to inhibit population growth or block the spread of the invasive nematode to control pine wilt disease.The gene daf-8 plays crucial roles in larval development and dauer formation in Caenorhabditis elegans,but little is known about its orthologue in B.xylophilus.In the present molecular characterization and functional analysis of daf-8 in B.xylophilus(Bx-daf-8),RT-qPCR showed that...     

Estimation and testing of linkages between forest structure and rainfall interception characteristics of a Robinia pseudoacacia plantation on China's Loess PlateauOA

Understanding the interaction between canopy structure and the parameters of interception loss is essential in predicting the variations in partitioning rainfall and water resources as affected by changes in canopy structure and in implementing water-based management in semi arid forest plantations.In this study,seasonal variations in rainfall interception loss and canopy storage capacity as driven by canopy structure were predicted and the linkages were tested using seasonal filed measurements....     

Improved guidelines for any-aged forestryOA

Any-aged forest management(AAF) is a means to reduce clear-felling without compromising profitability or timber production.The concept of AAF is to choose between clear-felling or thinning one harvest at a time based on what is better at that time in terms of the management objectives for the forest.No permanent choice is made between rotation forest management(RFM) and continuous cover forestry(CCF).Optimized AAF is never less profitable than RFM or CCF because all cutting types of both RMF and...     

Comparative analysis of thinning techniques in pine forestsOA

Thinning is a necessary and complex forestry activity. The complexity increases due to theoretical disagreements, contradictory recommendations, and errors of modern practice, which require confirmation through longtime experiments. This article presents a summary of experimental results from plantations established 20–30 years ago and explains concepts of the theory, methods, and regime of thinning in permanent sample plots of pine stands in Gatchinsky forest of the Leningrad region. The resear...     

Spatial pattern analysis of forest trees based on the vectorial markOA

Analysis of spatial patterns to describe the spatial correlation between a tree location and marks(i.e., structural variables), can reveal stand history, population dynamics, competition and symbiosis. However, most studies of spatial patterns have concentrated on tree location and tree sizes rather than on crown asymmetry especially with direct analysis among marks characterizing facilitation and competition among of trees, and thus cannot reveal the cause of the distributions of tree locations...     

松材线虫与拟松材线虫的几种鉴别方法

在形态、生化与分子以及致病性3个方面综述了松材线虫和拟松材线虫的鉴别方法,旨在为松材线虫病的防治和进出口检疫提供更多更安全的检疫方法,同时为更好的区别两种线虫提供理论依据。     

几种物质对松材线虫的作用

松材线虫病是松树的一种毁灭性病害。本文选用了几种物质，采用浸泡生测法和棉球生测法测定了其对松材线虫的作用。结果表明，阿维菌素对松材线虫的杀线活性较强，米乐尔次之，狼牙刺种子粗提物和氯化铵的杀线活性均较弱，氯化钙则无杀线活性。阿维菌素和米乐尔对松材线虫繁殖均有较强的抑制作用，狼牙刺种子粗提物的抑制作用较弱，氯化铵无抑制作用，而氯化钙对松材线虫的繁殖具有促进作用。     

8种化学药剂单独及两两联合染毒对松材线虫杀灭作用试验

8种药剂单个药剂的染毒结果表明，阿维菌材线虫即有较强的杀灭活性，其半数致死浓度（LC50）分别为0．0601mp／L和8.35mg／L，其LC50的95％可信区间（95％CI）分别为0．0416～0．0868mg／L和6．16～11．34mg／L。甲胺磷对松材线虫的毒性次之，其IC50为3282．46mg／L（95％CI为2779．71～3872．58mg／L），其它几种测试药剂（三邻甲苯基磷酸酯、甲醚菊酯、溴氰菊酯和吡虫啉）的杀线活性很弱。联合染毒测定的结果表明，阿维菌素与硫酸铜、溴氰菊酯与硫酸铜以及溴氰菊酯与涕灭威分别联合使用对松材线虫表现出毒性增强作用（P〈0．01），蜕明这几荆坝临嬉秭职抖燃虫的毒杀作用具有协同效应。     

松材线虫病综合预防技术研究

对松林中的枯死木、流通领域的松木及其制品,以及树体内的活体松褐天牛肢体进行抽样和分离监测,研究松线材虫病的综合监测预警技术体系.并且将外地调入和本地调出的森林植物及其产品全面实施动态源头管理,使所有监测对象都在预防控制管理渠道之中,形成操作性强和简便实用的长效管理机制.     

从文献分析看我国松材线虫病研究进展

本文从文献学入手，对我国松材线虫病Ｂｕｒｓａｐｈｅｌｅｎｃｈｕｓｘｙｌｏｐｈｉｌｕｓ研究的文献量、文献源及文献作者单位进行分析；从病理学的角度，对我国松材线虫病的研究进展进行评价。从文献学和病理学两个方面反映我国松材线虫病的研究现状和水平，为今后的深入研究和生产防治提供参考     

松材线虫SCAR标记与检测技术

将松材线虫RAPD特异片段OPM05-X2100进行分离、回收,与载体pGEM-TVector连接,转化大肠杆菌并培养,对目标克隆测序。根据测序结果,用Oligo5.0软件设计引物,正向引物为M05F2(5’-CGGGT CATGG CTGGA GGTAT CGT-3’),反向引物为M05R1(5’-TGGCT CAATG GCAAA TCCTT CGTA-3’),成功地将松材线虫特异片段OPM05-X2100通过引物对M05F2/R1转化为SCAR-M05-X600。运用SCAR标记引物M05F2/R对枯死松树体内分离的92份线虫样本的DNA进行标记,并对单条线虫经简易方法提取的DNA进行检测。结果表明:引物组合对所有81份松材线虫株系均扩增出一条600bp的清晰、明亮的条带,而对8份拟松材线虫、1份霍夫曼尼伞滑刃线虫、1份大核滑刃线虫、1份长尾属线虫均无扩增产物。该对引物可以检测单条松材线虫。利用这对特异引物组合可构建松材线虫检测试剂盒,实现对松材线虫的快速检测的目标。     

松材线虫病的MEP,MPP喷雾防治试验报告

试验表明,日本国配制的农药MEP乳剂,在松墨天牛羽他始期和高峰期各施1次,能使当年松树枯萎率下降到0．3％～0．7％,比对照组净降低8.4％～17．5％,具有推广使用价值;MPP油剂对枯死木内的松墨天牛羽化抑制作用不大,不能代替熏蒸剂推广使用。     

松材线虫病死木处理试验

为探索松材线虫病死木的利用问题，作者从1988年起，先后在松材线虫病发生地6家木制品厂进行了病死木处理试验，其工艺流程是病死木制材后加温烘干，温度65－120℃，杀灭了松材线虫和松褐天牛，进而在木板上涂胶、高温高压下（140－150℃，7－10kg/cm^2)压成不同规格的层压胶合板。工艺是安全可行的。松材线虫病死木处理试验结果表明，这是控制松材线虫病扩散蔓延的有效途径之一。     

温度对松材线虫的生物效应

对松材线虫在不同温度下的存活及生长繁殖状况进行了观察。松材线虫在-70℃不能存活,在-20℃可存活约8d,在10℃~35℃的温度范围内,松材线虫的生长繁殖速度随温度上升而加快,生长繁殖数量随温度提高而增加,松材线虫在40℃可存活约7d,在45℃可存活约5d,在50℃以上不能存活。松材线虫与松树在不同温度下生长速度的差异提示松树在不同气候条件下发病轻重与此差异有关。     

松材线虫病生物防治研究进展

松材线虫Bursaphelenchus xylophilus是外来入侵生物,主要依靠媒介昆虫的携带在自然界中扩散传播。目前松材线虫病的生物防治研究主要集中在对松材线虫本身及其传播媒介——松墨天牛的控制两方面。本文对国内外松材线虫病的生物防治方法研究做了总结。