内蒙古大兴安岭东南部林区蒙古栎林物种多样性的初步研究

文章通过对内蒙古大兴安岭东南部林区蒙古栎林物种多样性的调查研究,掌握了蒙古栎林在不同季节里物种数量变化情况,为今后保护、经营利用蒙古栎林提供第一手基础资料。     

冀北山地蒙古栎次生林的林分结构与生物量调查研究

蒙古栎次生林是冀北山地森林植被的重要组成。该文以阴坡25a生的蒙古栎次生林为研究材料,对其林分乔、灌树种和草本植物组成及林木胸径结构进行了分析;以胸径为自变量建立了生物量模型,参照现有森林经营抚育技术规程开展了抚育试验,对产材量进行了评价。     

蒙古栎的育苗技术

蒙古栎(柞树)(Quereus moogolica Turca),属壳斗科栎属,材质经济价值高,根系发达,深根、耐寒、耐干旱,抗风、防水能力强,枝干可做矿柱、地板,也可用来培养木耳、香菇等,种子含淀粉及其它营养物质,是良好的饲料,是我国著名的硬阔叶树种,也是围场县水源涵养林和水土保持林、薪炭林的优良树种,几年来围场县试验作防风治沙和阳坡`栽植树种,作者根据围场的立地条件,对该树种进行试验性繁育,取得成功,现将其繁育技术介绍如下.     

长白山区天然蒙古栎林空间分布规律的研究

从吉林省红石林业局森林资源调查小班中筛选出天然蒙古栎小班,利用ArcGis对蒙古栎小班进行空间热点分析.结果表明:显著热点分布区蒙古栎小班3193个.其中,在不同坡度级上主要分布在坡度适中的斜坡,小班个数可达1506个;在不同坡位上主要集中在坡中,小班个数可达1290个;在不同坡向上主要分布在东南、南和西南等阳坡、半阳...     

森林火灾后蒙古栎林碳素分布及储量的分析

以黑龙江塔河林业局施业区内的杜香—蒙古栎林和草类—蒙古栎林为对象,对火灾前后碳素的分布和储量进行了研究。结果表明:森林火灾发生后,蒙古栎林地上、地下部分的碳储量均表现为减少。杜香—蒙古栎林碳储量变化量为-33.812 9 t.hm-2,其中:地上部分为-0.499 4 t.hm-2,地下部分为-33.313 5 t.hm-2,贡献率分别为1.5%和98.5%;杜香—蒙古栎林碳储量变化量为-104.944 6 t.hm-2,其中:地上部分为-76.452 7 t.hm-2,地下部分为-28.491 9 t.hm-2,贡献率分别为72.9%和27.1%。蒙古栎林地上、地下火灾前后碳储量的分布与变化同林分类型密切相关。     

高寒区蒙古栎的栽植与管护

一、蒙古栎的生物学特性蒙古栎是国家二级珍贵树种,是我国北方林区中主要的次生林树种。主要分布在东北、华北、西北各地,华中地区亦少量分布。蒙古栎树高可达30米,胸径1米多,喜光、耐寒、喜凉爽气候,耐干旱、耐瘠薄,通常生于向阳干燥山坡。对土壤要求不严,酸性、中性     

湖南省森林植被的碳贮量及其地理分布规律

基于湖南省第4次(1990～1995年)森林资源调查资料,结合生物量测定数据,估算了湖南省森林植被的碳贮量和碳密度,分析了它们的地理分布规律和植被类型特性.结果表明:湖南省森林植被碳贮量为173.974 Tg,在14个地州市中,怀化市的森林植被碳贮量最大,为31.047 Tg,其它依次是永州市、郴州市和邵阳市,它们的森林植被碳贮量分别为21.527、19.306和19.239 Tg,各森林类型中,杉木林的碳贮量最大,为51.588 Tg,占湖南省碳贮量的29.65%;湖南省森林植被的平均碳密度为15.88 t·hm-2,各地州市森林植被的平均碳密度变化为12.01～17.95 t·hm-2,各森林类型中阔叶林的碳密度最大,为32.45 t·hm-2,是湖南省森林植被平均碳密度的2倍多.     

根河:秀美的自然风光

根河市地处大兴安岭北部西部,是我国纬度最高的城市之一,属寒温带湿润型森林气候,平均气温-4.1℃,极端最低气温-49.6℃,是内蒙古自治区平均气温最低的城市。全市总人口18万,总面积20012平方公里,森林面积174.5万公顷,森林覆盖率87.2%。这里有较为珍贵的树种181种,野生动物300余     

浅谈应用地理信息系统绘制地形林相图

文章以地理信息系统软件ArcGIS、森林资源监测与管理GIS系统软件、EzMap为平台,介绍绘制地形林相图的方法和技巧。     

江西胡颓子属植物种类与地理分布

基于野外调查和查阅标本、文献,运用相似性分析,研究江西胡颓子属植物的种类与地理分布。结果表明,江西境内共有胡颓子属植物12种1变种,江西南部与北部的胡颓子属植物种类存在差异,距27°N线越远,差异越大;江西胡颓子属植物与相邻地区胡颓子属植物相似性系数为0.4～0.81,表明江西与邻近地区胡颓子属植物区系关系密切。     

基于生态位模型的石蒜适生区预测

运用预设预测规则的遗传算法(GARP)和最大熵(MaxEnt)两种生态位预测模型,以及受试者工作曲线(ROC)分析方法,预测石蒜属石蒜潜在适生区.结果表明,GARP和MaxEnt模型ROC曲线下面的面积AUC(area under the ROC curve)均值分别为0.910和0.988,MaxEnt模型的AUC值更大,预测结果更准确,运行速度更快,更适合用于石蒜的适生区预测.对环境变量进行刀切法表明,在所有环境变量中,最冷季度平均温度对于石蒜分布的影响(贡献)最大,其次是年均温、最冷月的最低温度和最暖季度降水量,而海拔、降水量变化方差对石蒜分布的影响比较小.预测结果显示,石蒜在世界范围内主要分布在亚洲东部以及亚洲中部一小部分,另外北美洲的东部,欧洲南部一小部分地区也适合其生长.在中国范围内主要分布在云南、贵州、福建、江苏、浙江、安徽、江西、重庆、湖北、湖南等省,以及山东、河南、陕西、甘肃等省南部;四川东部和广东、广西(除了南部沿海地区)均预测为适生区,海南、台湾、西藏部分地区也是适生区.     

Effect of Japan Sea climate on geographic distribution ofCastanopsis sieboldii andC. cuspidata

The geographic distributions ofCastanopsis sieboldii andCastanopsis cuspidata overlap each other on the Pacific coast of Japan, but on the Japan Sea coastC. sieboldii tends to dominate at similar temperatures. The authors attempted to explain this phenomenon by analyzing the effects of climatic factors. Nuts were collected from the Pacific and Japan Sea coasts of the Kinki and Chugoku districts, and the nut characteristics and the number of layers of epidermis in the leaves of the seedlings were investigated. The distribution ofC. sieboldii andC. cuspidata was satisfactorily explained by a multiple regression equation that was developed using three climatic factors: maximum snow depth in winter, lowest temperature in the coldest month, and annual mean temperature, out of fourteen such factors that were considered. The estimated distribution ofC. sieboldii andC. cuspidata from the multiple regression equation agreed with 66.2% of the actual observations.     

山东省木本植物区系的地理联系与树木引种驯化对策的探讨

通过分析山东省木本植物区系的地理联系，结合外来树种在山东省的生长表现，初步探讨了山东省进行树木引种的原则和方向。     

对完达山林区森林分布及类型的探讨

分析了完达山区域水平地带性和垂直地带性的森林特征,并对该林区不同区域分布的不同森林类型进行了评价。     

Identification and geographic distribution of vegetative compatibility types of Cryphonectria parasitica and occurrence of hypovirulence in Greece

Castanea sativa, one of the most precious forest trees in Greece, is affected by the spread of chestnut blight all over the country. Identification and mapping of the vegetative compatibility (vc) types of the fungus Cryphonectria parasitica was carried out and the occurrence of hypovirulence was checked. In 11 chestnut populations distributed all over Greece, 627 isolates were obtained and their vc type was determined. Four vc types were identified by means of tester isolates: EU‐12 was found to be the dominant vc type reaching a percentage of 88%, with EU‐2 (6%), EU‐10 (3%) and EU‐1 (2%) following. EU‐12 was found in all 11 populations investigated whereas EU‐2 was isolated from five populations and EU‐10 and EU‐1 were found only in one population each. Natural hypovirulence was also found in five populations of 11 examined. Perithecia were not found in either population, a finding supported by the fact that all Greek isolates examined belonged to a single mating type, MAT‐1. The low diversity in vc types, the absence of the perithecial stage and the occurrence of natural hypovirulence in some areas support the feasibility of successful application of biological control on the national level in Greece.     

Survey of predacious mites on citrus in South Africa. Specific diversity, geographic distribution and the abundance of predacious mites

During a survey (March–June, 1995) of predacious mites on citrus in 30 major production areas, 25 species of phytoseiid and Anystid mites were recorded.Amblyseius pafuriensis Van der Merwe occurred almost at every sites in the Northern Transvaal and Southern Zimbabwe,A. citri (Van cer Merwe & Ryke) was most common in Central and Eastern Transvaal,A. citri andTyphlodromus crassus Van der Merwe, Natal, andA. addoensis addoensis (Van der Merwe & Ryke) andA. addoensis rubicolus (Van der Merwe & Ryke) in both Cape provinces. Regarding the whole region,A. addoensis addoensis, A. citri, A. addoensis rubicolus represented 86% of the total number of sampled predators,A. pafuriensis, T. crassus andT. rasilis Van der Merwe together represented 5% and the remaining 20 species represented 9%. The study indicated thatA. pafuriensis, T. crassus andT. rasilis can be excellent biocontrol agents on citrus.     

STUDY ON GEOGRAPHIC VARIATION OF DAHURIAN LARCH IN CHINA

Based on the main characteristies of growth,ohenology and resistance at both seed-ling stage (one year old) and sampling stage (seven years old) of Dahurian larch (Larix gmelinii(Rupr.)Rupr.) from seventeen provenances in China ranging from 47°10′ to 52°25′N and 119° 57′to 130°25′E,the rules and patterns of infraspecific geolgraphic variation have been studied by　using variance analysis,corelation analysis,partial correlation analysis and regression analysis.The best provenance for local site and its neighborhood was selected according to the growth char-acteristies of seven years provenance test on Liangshui Experimental Forest Farm of NortheastForestry University.