Effect of aspect on the structure of some natural stands of Abies pindrow in Himalayan moist temperate forest

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.     

扑救森林火灾时的注意事项

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。     

请留下最后一片原始森林——立即禁止砍伐新疆残存山地原始林的建议

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。     

Why the Conservation of Forest Genetic Resources Has Not Worked

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.     

The Combined Effects of Remnant Vegetation and Tree Planting on Farmland Birds

Abstract:  Biodiversity conservation on agricultural land is a major issue worldwide. We estimated separate and joint effects of remnant native woodland vegetation and recent tree plantings on birds on farms (approximately 500–1000 ha) in the heavily cleared wheat and sheep belt of southern Australia. Much of the variation (>70%) in bird responses was explained by 3 factors: remnant native-vegetation attributes (native grassland, scattered paddock trees, patches of remnant native woodland); presence or absence of planted native trees; and the size and shape of tree plantings. In terms of the number of species, remnant native vegetation was more important than tree planting, in a 3:1 ratio, approximately. Farms with high values for remnant native vegetation were those most likely to support declining or vulnerable species, although some individual species of conservation concern occurred on farms with large plantings. Farm management for improved bird conservation should account for the cumulative and complementary contributions of many components of remnant native-vegetation cover (e.g., scattered paddock trees and fallen timber) as well as areas of restored native vegetation.     

The Paradox of Forest Fragmentation Genetics

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.     

广州帽峰山林区空气负离子动态及与环境因子的关系

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.     

天然林林龄的模拟估算及案例

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.     

三峡库区不同植被覆盖对土壤碳的影响

植被覆盖变化对三峡库区生态环境产生重要影响.土壤有机碳在陆地生态系统的发育和运行等方面均起着极其重要的作用,所以本课题研究宜昌点军区柏树地,橘树地以及菜地的土壤性质状况.结果表明:土壤含水量是柏树林最大.菜地的最小,而土壤容重的大小顺序是:柑橘树地>柏树地>菜地.土壤有机碳、易氧化碳和二者的比值都是柏树地的最大,柑橘地的最小,菜地的处于中间状态.而微生物碳和微生物墒含量大小顺序是柏树地>柑橘树>菜地;微生物代谢墒的大小顺序是:柑橘地>菜地>柏树地.由此说明柏树生长有利于土壤活性碳源含量的提高和土壤质量的改善.     

天然次生林人工更新后对土壤物理性质及碳贮量的影响

天然林被人工林取代后对土壤水文物珲性质及土壤碳贮量有重要的影响.文章以海南天然次生林人工更新为尾细桉(Eucalyptus urophylla×E.tereticornis)和马占相思(Acacia mangium)林前后的土壤为研究对象,研究分析了人工植被更新对土壤水文物理性质和土壤碳贮量的影响.结果表明:天然次生林更新为桉树、马占相思人工林后,土壤容重增加,土壤总孔隙度、毛管孔隙度和非毛管孔隙度减小,0～80 cm土壤的最大贮水量、毛管贮水量和非毛管贮水量降低,桉树和马占相思人工林最大贮水量分别降低19.8 mm和43.3mm,桉树人工林0～40cm土壤碳贮量降低6.77t·hm-2,马占相思人工林的增加14.68t·hm-2.