社区林业政策对尼泊尔农村生计的影响

尼泊尔引入社区林业管理已有20多年。虽然有社区林业管理促进了公有林和私有林树木生长的报道,但其对当地社区获得林产品,如木材、薪柴,以及其他非木材林产品(NWFP)的促进作用还没有完全得到证实。此外,社区林业的介入有明显的社会效益。通过资料收集和实地考察分析了尼泊尔中部山区执行社区林业政策对社会经济的影响。     

彩色豆马勃菌剂的应用研究

外生菌根真菌——彩色豆马勃(豆包菌)Pisolithus tinctorius(Pers.)Coker and Couch(简称P_t)。应用彩色豆马勃商品化菌剂对我国一些重要用材树种进行菌根化的研究,评价这些树种对P_t菌剂的反应,各种菌剂的效果及其应用前景,为在我国林业生产和环境保护中推广和应用P_t技术及其菌剂提供基础。     

Monitoring Forest Fire with MODIS-NDVI Images in Beijing

INTRODUCTION The moisture content of fuel is a critical parameter in fire ignition because flammability is closely dependent on it (Dimitrakopoulos et al. 2001). Dead fuel lying on the forest floor (fallen branches, litter, foliage) is the most dangerous because it is drier than live fuel and more dependent on rapid atmospheric changes. The moisture content of live fuel plays a marginal role in fire ignition, but it is critical in fire propagation modeling because the amount of water is d…     

Assessing Threats and Setting Conservation Priorities for Plant Species between Forest and Meadow Ecotone in Sanjiangyuan Nature Reserve, China

INTRODUCTIONA large number of nature resources have fosteredhuman beings in the world. However, during the lastfew decades these nature resources and biodiversitywere subjected to various anthropogenic pressuressuch as plantation, deforestation, construction ofhydro-electric project, overgrazing and exploitation andother developmental activities (He Youjun, et al, 2004b;Li Ang, et al, 2002; Swamy, et al, 2000). In order toprotect environment and biodiversity, we have to facethe challenge…     

Analysis of Sediment Source of Watershed in Western Shanxi of the Loess Plateau

1 INTRODUCTIONThe Loess Plateau is the most drastic soil erosion regionin China, with the most severe water erosion. Thedistribution of types and intensity of erosion not onlyhave regional diversity but also have perpendicularvariation. In the small watershed, there are differencesin erosion characters among its upper, middle and lowerreaches. It is very significant for taking rationalmeasures of soil and water conservation and forpreventing soil and water loss to analyze the relationbe…     

Researches and Application of Fuelbreaks in China

The fuelbreaks were established in south China from 1950s. With the active work of local communities and state government, the fuelbreaks have been built for 398,000 kilometers. In some areas, fuelbreaks and firebreaks have constructed a network primarily, such as in the provinces of Fujian, Guangdong, Guangxi. The fuelbreaks can prevent forest fire effectively. That has been approved by actual examples and burning tests. The fuelbreaks also benefit the forest ecosystem and environment. This paper makes a review on fuelbreaks research and application in China, discussed present research achievements about fuelbreaks mechanism and its development. In the future, the Chinese government and local communities will increase investment in the construction of firebreaks network with fuelbreaks as focal points.     

美国枫香组织培养胚状体的发生

美国枫香(Liquidamber Styraciflua)最初在固体培养基上长出的愈伤组织,移置到液体培养基上悬浮培养时,分化出正常形和畸形两种不定胚;再转移到固体培养基上培养时,从畸形不定胚叶处分化出许多次生不定胚。鱼雷期胚可以发育成正常植株。在琼脂培养基上培养时,也观察到了胚状体的发生。     

美国梧桐树病虫害(上)

叶部害虫1、网蝽:美国梧桐网蝽(Corythucaciliata)遍及美国东部,是一种危险性害虫,因成虫体上覆有纱罗状或网状翅而得名。若虫黑色扁平,体多刺。成虫和若虫群聚叶片上并吸食为害。被害叶成白色或棕色,形似叶蝉及螨类为害所形成的斑点、点刻和褪色斑。严重受害的叶片成褐色并早落。该虫不长严重大爆发,但每年都有零星、少量的爆发。最严重的为害最易见于市区的遮阴树和观赏树。干旱的夏末损害最显著。成虫蛰伏于寄主及其附近的落叶,枯树皮或其它隐蔽的场所内越冬。春天活动并爬     

Research and Conservation of Forest Genetic Resources in China

The present situation of forest tree genetic germplasm resources research and conservation in China is introduced which including the background, decision-making of conservation strategies and principles, the plan of area division and tree species classification, the sample strategy of germplasm conservation, the advances in conservation pattern and related technologies research, the achievements of germplasm conservation and utilization in China, and the problems to be solved. The recent achievements and data related are listed.     

秦岭松栎林带生物量及其营养元素分布特征

秦岭脱齿栎林、油松林和华山林（包括０－６０cm土层）营养元素总贮量达２９．２５００－３９０．１７３９t.hm^-2，其大小为锐齿栎林＞华山松＞油松林，土壤中营养现贮量占系统总量的９３．１０％－９９．３９％，植被层和凋落物层仅占０．５７％－３．００％和０．１０％－１．９９％；３林分乔木层生物量、木材蓄积量和营养元素积累量平均值分别为１２０．４８３t.hm^-2,129.384m^3.hm^-2和１２２６．９kg.hm^-2，锐齿栎林＞油松林＞华山松林。３林分林下植被层生物量现存量和营养元素积累量平均值分别为１．５５３t.hm^-2和５３．１kg.hm^-2，锐齿栎林最大，华山松林最小。林下凋落物现存量和营养元素积量平均值分别为１７．４７５t.hm^-2和５０２．５kg.hm^-2，３林分凋落物现存量、营养元素含量及其积累量都存在明显的差异。锐齿栎林、油松林和华山松林营养元素年吸收量、归还量、存留量和平均归还率分别为３３．４、１４７．２和２６４．３，１９５．６、６６．９和８４．１，１３８．８、８０．４和１８０．２kg.hm^-2和０．５８５、０４５４和０．３１８，３林分各营养元素的年吸收量，归还量和存留量也存在一定的差异，锐齿栎林干和皮中Ｃa和Ｍg含量远远高于油松林和华山松林的，锐齿栎林多代连作势必导致营养元素的大量流失，特别是Ｃa和Ｍg，会破坏土壤原有离子动态平衡，引起林地土壤理化性质改变，林地生产潜力逐渐下降。