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581.
本文创造性地提出了国有林场“三工”合同管理的新模式,走法制化的道路,首先必须理顺国有林场与“三工”与“三工”组织的劳动关系,依照《劳动法》与《合同法》,分清各自的权利和义务,然后逐步由“三工”组织劳动合同向经济承揽合同过渡,依法解决合同管理中存在的问题。  相似文献   
582.
Annual and seasonal home ranges were calculated for 47 Eurasian lynx in four Scandinavian study sites (two in Sweden and two in Norway). The observed home ranges were the largest reported for the species, with study site averages ranging from 600 to 1400 km2 for resident males and from 300 to 800 km2 for resident females. When home range sizes were compared to the size of protected areas (national parks and nature reserves) in Scandinavia, it was concluded that very few protected areas contained sufficient forest to provide space for more than a few individuals. As a direct consequence of this, most lynx need to be conserved in the multiuse seminatural forest habitats that cover large areas in Scandinavia. This conservation strategy leads to a number of conflicts with some land uses (sheep and semidomestic reindeer herding, and roe deer hunters), but not all (forestry and moose harvest). Accordingly research must be aimed at understanding the ecology of these conflicts, and finding solutions.  相似文献   
583.
The effects of aspect, altitude, and slope have been observed on the moist temperate forests of Abies pindrow Spach in the Garhwal Himalaya, India. Four aspects, namely, north-east, north-west, south-east and south-west, have been studied to understand the growth behaviour of A. pindrow at varying altitudes. The total basal cover was found to be highest (5099.6 cm2/100 m2) on the north-east facing slopes, and lowest (3092.7 cm2/100 m2) on the south-east facing slopes. The A. pindrow was found to be associated with Quercus semecarpifolia as a main companion species on all the faces, whereas, Lyonia ovalifolia, was associated only on the west facing slopes.  相似文献   
584.
总结分析了在林火扑救中指挥员应掌握了解的基本情况及扑火队员应注意的事项。  相似文献   
585.
干旱区的山地是平原区河流的水源聚积地,而山地森林更是水源的涵养林,对保证和供给山下绿洲资源水源有重要调节作用,山地森林还在保持水土、生物多样性保护、旅游、文化、教育等多方面有重要生态作用。其生态经济价值是其本身木材价值的许多倍。但过去我们对森林的生态价值认识不足,林业部门只把它当资源进行过度砍伐,以获取直接经济效益,新疆天山及阿尔泰山水源涵养林自50年代以来能砍的几乎全部砍完,仅剩两条山脉西端小面积残存未砍伐的原始森林。为了子孙后代,为了环保工程,应立即停伐。  相似文献   
586.
利用柑桔加工过程中的废物生产纤维素酶发酵饲料   总被引:6,自引:0,他引:6  
利用柑桔加工过程中废物提取有用物质后 ,再进行固体发酵生产纤维酶发酵饲料的研究 ,筛选到一株具有较高纤维素酶的青霉菌株。其最适固体培养基配方为 :桔皮∶豆饼∶麸皮 =15∶1∶1,碳酸铵质量分数为 3% ,物料∶水 =2∶1,pH值为 4 5 ;最佳产酶条件为 :培养温度为 30℃ ,培养时间为 84h左右。为柑桔加工过程中所产的废物提供了一条变废为宝 ,解决环境污染的新途径。   相似文献   
587.
Why the Conservation of Forest Genetic Resources Has Not Worked   总被引:3,自引:0,他引:3  
Abstract:  Genetic diversity is indispensable for long-term forest sustainability and is therefore mentioned in numerous binding and nonbinding political covenants calling for action. Nevertheless, there are significant obstacles to the conservation of forest genetic resources. We discuss hindrances to genetic conservation, mainly in Europe. We identified impediments by reviewing the literature and on the basis of the experiences of the authors in this field and their participation in related political processes. The impediments include (1) difficulties in assessing and monitoring genetic erosion and human impacts (e.g., by the lack of markers showing adaptive variation and the lack of record keeping on the use and transfer of forest-tree germplasm), (2) complexities of European national structures that make the development of a common strategy toward forest genetic conservation problematic, (3) lack of effective forest governance in many parts of the world, (4) the general unattractiveness of genes as flagships in raising public awareness, (5) lack of integration of genetic aspects into biodiversity conservation, and (6) the fact that scientists and politicians are often at cross-purposes. To overcome these impediments, forest geneticists and their peers in species conservation have to participate more actively in decision making. In doing so, they must be prepared to face challenges on 2 fronts: participating in political processes and the provision of significant research findings to ensure that decisions with respect to forest genetic diversity are politically implementable and effectively address targets.  相似文献   
588.
The Paradox of Forest Fragmentation Genetics   总被引:5,自引:0,他引:5  
Abstract:  Theory predicts widespread loss of genetic diversity from drift and inbreeding in trees subjected to habitat fragmentation, yet empirical support of this theory is scarce. We argue that population genetics theory may be misapplied in light of ecological realities that, when recognized, require scrutiny of underlying evolutionary assumptions. One ecological reality is that fragment boundaries often do not represent boundaries for mating populations of trees that benefit from long-distance pollination, sometimes abetted by long-distance seed dispersal. Where fragments do not delineate populations, genetic theory of small populations does not apply. Even in spatially isolated populations, where genetic theory may eventually apply, evolutionary arguments assume that samples from fragmented populations represent trees that have had sufficient time to experience drift, inbreeding, and ultimately inbreeding depression, an unwarranted assumption where stands in fragments are living relicts of largely unrelated predisturbance populations. Genetic degradation may not be as important as ecological degradation for many decades following habitat fragmentation.  相似文献   
589.
广州帽峰山林区空气负离子动态及与环境因子的关系   总被引:3,自引:0,他引:3  
采用定位连续观测方法,研究了广州帽峰山森林公园负离子含量近5年的年、季、月变化及不同天气的变化规律,并以此对帽峰山森林公园的空气质量进行了计量评价.分析了空气负离子含量与环境因子的相关关系.结果表明:林区不同观测区的负离子含量差异较大,山下瀑布空间负离子含量最高.平均水平达达2l 729 ions.cm-3;林内负离子含量年间及月间变化不大,沟谷小溪和山中部瀑布空间由于人为干扰,负离子含量年动态呈现降低趋势,山下瀑布空间年负离子含量维持在20000 iotis·cm-3左右;负离子含量的季节差异显著,春夏季大于冬秋季,夏季最高、冬季最低.空气质量评价系数CI的最低在2月份、最高在8月份.不同天气条件下负离子含量大小顺序为下雨>晴天>阴天.负离子含量与空气温度呈正相关,与空气湿度呈正相关.与空气气压呈负相关.  相似文献   
590.
天然林林龄的模拟估算及案例   总被引:1,自引:0,他引:1  
林龄是森林生态系统的一个重要特征,具有生态学意义.但是目前生态学调查中对天然林林龄的估算方法有一定缺陷.在特定的环境条件下,森林有着相应的演替过程.已有林窗研究表明.长白山森林是按照一定次序演替,森林的径级结构也是有规律可循的.由于总是缺乏足够的长期系统观测数据,因此作者采用数值模拟作为替代方法.应用校正过的林窗模型模拟0~600 a的森林演替序列,比较对长白山原始天然林的采样的结果,发现目前的林龄最接近400 a.这个估测结果可以从本地区历史资料记载得到印证.  相似文献   
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