不同类型林分土壤微生物生理类群分析

本研究就三种不同处理林分土壤微生物生理类群的初步分析,表明杉木马尾松混交后有利于固氮微生物的生长,固氮微生物数量的增加,促进了混交林分生长;有利于氨化细菌的生长,氨化细菌数量的增加,又利于提高含氮有机物的分解和转化速率,从而提高混交林地土壤肥力;同时促进了纤维素分解菌的生长,利于有机物的转化和加快碳素循环速率,从而为植物生长提供更多的碳素和能源。因此,在混交林中杉木的平均胸径比对照提高24%,平均树高比对照提高21%;马尾松平均胸径比对照提高20%,平均树高比对照提高19%,可见营造杉、马混交林比纯林更具发展潜力,可实现树高、胸径积累的双赢。     

Simulating responses of Northeastern China forests to potential climate change

IntroductionItissurethatpresentelevatiollsofCO2a11dotllergrcc11-housegasesinducedbyhumanactivitiesaren1akli1gglobalclimategothroughinexperielICedcl1anges(Scl1le-subgerl987).Thecurrentquasi-equilibriulllstatesofbio-sphereecosystCm,esPeciallyterrestrialecosystems,wouldbebrokenbecausetl1estructure,fu11ction,distributio11andtlledynamicsofanyexistedecosystemsareIberesultsoflongtermadaptationofbio-systemtocurrentclin1ate.Theec()systemsdistributedinhighlatitlldeareawouldhavemuchbiggerchai1ge(Bona…     

基于标准森林单位的中国乔木林资源物量核算方法与应用

森林资源核算是森林资源管理的基础，森林资源是数量与质量的统一体，全面的森林资源实物量核算应该综合考虑数量和质量2个方面。文中提出森林资源物量这一概念作为森林资源数量与质量的融合，进一步提出以“标准森林单位”为核算森林资源物量的基本单位，通过将质量参差不齐的各种森林折算为标准森林单位来核算森林资源物量；最后，基于中国第7和第8次全国森林资源连续清查乔木林省域汇总数据进行了试算。结果显示:乔木林资源物量最高的省份为黑龙江、内蒙古、云南等，最低的省份为上海、天津、宁夏等；第7和第8次森林资源清查间隔期间乔木林资源物量增幅最高的省份为江苏、天津、北京等，物量出现下降的为湖南和江西；根据森林资源清查各省份汇总数据计算的乔木林资源物量之和与根据全国汇总数据计算的乔木林资源物量相差不大，表明我们所建立的乔木林资源物量核算体系具有较强的一致性与稳定性。     

东北东部天然次生林的景观类型空间连接与分布规律--以黑龙江省帽儿山林场为例

帽儿山地区是东北东部山区较典型的天然次生林区。本文利用ARC／INFO软件，对帽儿山林场景观类型最小距离指数和景观连接度指数进行分析，进而对帽儿山林场各景观类型的空间分布规律进行了探讨。结果表明：有林地与无林地的景观连接度有明显差异，无林地的景观连接度普遍大于有林地；天然林的景观连接度都接近于O，景观破碎化程度较高。人工林的最小距离指数低于天然林和非林地；人工林中，人工针叶混交林的距离指数最小，格局接近于团聚分布；天然林的景观格局近于随机分布；非林地中，采伐迹地的距离指数最小，接近于团聚分布。图2参15。     

中国竹子的种植前途

在过去,中国竹类资源主要被农户作为林副产品自用,很少与市场关联。近年来,由于谷物供应的过剩和农业环境的恶化,大家都在寻找既能够保护环境又能满足市场需求的替代作物。竹子紧密关联着农、林二业,完全有可能用以应对中国农业面临的新挑战。在有记载的534种中国竹子中,153种生产可食竹笋,其中56种为优秀种;139种竹子可用于木材生产,其中58种为优秀种;116种竹子可生产优质竹篾,其中22种为优秀种;88种竹子适用于公园种植,其中34种为优秀种;45种竹子可生产纸浆,其中18种为优秀种。图5附录5参32。     

Analysis of Original Causes of Reed Fires in Zhalong Nature Wetland Reserve in Heilongjiang Province

Zhalong Nature Reserve is located in the border areaof Qiqihaer City, Fuyu County, Lindian County andTailai County of Heilongjiang Province. The area ofthe reserve is 210 000 ha. The reserve is the firstnature reserve for protecting wetland and crane inChina. There were more than 300 red-crownedcranes here at the very most. Zhalong Nature Reserveis situated at the Songnen Plain, the lower stream ofthe Wuyuer River. It is the biggest nature reserve inChina that takes crane and wetland …     

The status and conservation of whooper swans (Cygnus cygnus) in China

There are five species of swan in the world. Three of them were recorded in China. They are whooper swan (Cygnus cygnus), whistling swan (Cygnus columbianus) and mute swan (Cygnus olor). Among them. whooper swan is the most famous in China. Whooper swan is a resident bird in China. They breed in Xinjiang Ugyur Autonomous Region. Inner Mongol Autonomous Region. Heilongjiang Province. etc., and winter in Qinghai. Shandong. Henan Province, etc, and the lower reaches of the Changjiang River. The total number in China is about 5.000 in breeding grounds and 15.000 in wintering grounds. Higher number were found in 1960s. Because of the changes in environment and hunting, of picking up eggs and of catching nestlings, their population is being reduced rapidly. They are in danger now. In order to protect the whooper swans, some protection measures must be taken, such as strengthening public education and scientific research, estabilshing a base of raising and breeding: developing international cooperation, strengthening the construction of natural reserves in the breeding and wintering grounds. Up to the end of 1993. 34 natural reserves have been established in China. (Responsible Editor: Sun Yueqi)     

The role of fire in forest dynamics in Daxinganling region

Recent fire statistics and preliminary fire history data suggest that fire has been historically responsible for maintaining the vegetative communities up to present in Daxinganling region. Forest types, and even tree species, arc dependent on the degree of fire intensity, fire size, depth of burn and fire frequency. Selected samples of larch, pine, birch and spruce forest were studied in terms of species composition as determined by fire frequency which mainly depends on topography and site conditions. Intervals between fires range between 6 and 170 years.