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1.
Terrestrial ecosystems represent a major sink for atmospheric carbon(C) and temperate forests play an important role in global C cycling, contributing to lower atmospheric carbon dioxide(CO_2) concentration through photosynthesis. The Intergovernmental Panel of Climate Change highlights that the forestry sector has great potential to decrease atmospheric CO_2 concentration compared to other sectoral mitigation activities. The aim of this study was to evaluate CO_2 sequestration(CO_2 S)capability of Fag us sylvatica(beech) growing in the Orfento Valley within Majella National Park(Abruzzo,Italy). We compared F. sylvatica areas subjected to thinning(one high-forest and one coppice) and no-management areas(two high-forests and two coppices). The results show a mean CO_2 S of 44.3 ± 2.6 Mg CO_2 ha~(-1)a~(-1),corresponding to 12.1 ± 0.7 Mg C ha~(-1) a~(-1) the no-managed areas having a 28% higher value than the managed areas. The results highlight that thinning that allows seed regeneration can support traditional management practices such as civic use in some areas while no management should be carried out in the reserve in order to give priority to the objective of conservation and naturalistic improvement of the forest heritage.  相似文献   

2.
Repeated biomass harvesting for human livelihood needs can cause significant changes in forest structure, composition and diversity. Such impacts have often been associated with the distance to villages and their size, but the effects of individual villages in relation to their characteristics have been little studied. Focussing on the issues around communities’ impacts on the forest, this research aimed to understand how resource extraction by two Buffer Zone villages in Nepal's Bardia National Park affects forest structure and diversity. Tree density, basal area, diameter at breast height (DBH), species richness, two diversity indices and disturbance indices were recorded in 108 plots in 12 transects, from March till May 2005, within the park along the village boundaries, where resource extraction occurs, and in the core park area which is isolated from human disturbance. Forest subject to resource extraction had a lower density of trees, smaller DBH and lower species richness and diversity. Forest disturbance declined with distance from the villages but the two villages differed widely in their impact on the forest. Resource use was more intensive in Shivapur village and percentage of trees lopped, average lopping intensity and numbers of dung piles were statistically significant. This was mainly due to the lack of access to Buffer Zone community Forest for Shivapur households. Interviews with villagers suggested that there have been changes in species availability compared to 5 years ago. Households also underestimated the impact of their resource extraction, which may prevent them from changing their behaviour to benefit conservation. It is clear that understanding rural communities’ needs, their framing of resource extraction and utilisation, and dependence on forest resources will be very helpful for long term conservation measures.  相似文献   

3.
The extensive area of degraded tropical land and the calls to conserve forest biodiversity and sequester carbon to offset climate change demonstrate the need to restore forest in the tropics. Deforested land is sometimes replanted with fast-growing trees; however, the consequences of intensive replanting on biomass accumulation or plant and animal diversity are poorly understood. The purpose of this study was to determine how intensive replanting affected tropical forest regeneration and biomass accumulation over ten years. We studied reforested sites in Kibale National Park, Uganda, that were degraded in the 1970s and replanted with five native tree species in 1995. We identified and measured the size of planted versus naturally regenerating trees, and felled and weighed matched trees outside the park to calculate region-specific allometric equations for above-ground tree biomass. The role of shrubs and grasses in facilitating or hindering the establishment of trees was evaluated by correlating observed estimates of percent cover to tree biomass. We found 39 tree species naturally regenerating in the restored area in addition to the five originally planted species. Biomass was much higher for planted (15,675 kg/ha) than naturally regenerated trees (4560 kg/ha), but naturally regenerating tree regrowth was an important element of the landscape. The establishment of tree seedlings initially appeared to be facilitated by shrubs, primarily Acanthus pubescens and the invasive Lantana camara; however, both are expected to hinder tree recruitment in the long-term. Large and small-seeded tree species were found in the replanted area, indicating that bird and mammal dispersers contributed to natural forest restoration. These results demonstrate that intensive replanting can accelerate the natural accumulation of biomass and biodiversity and facilitate the restoration of tropical forest communities. However, the long-term financial costs and ecological benefits of planting and maintaining reforested areas need to be weighed against other potential restoration strategies.  相似文献   

4.
根据所调查样方的树种综合优势比值,对广东西部(粤西)廉江谢鞋山次生季雨林最重要的三个建群树种,进行了空间格局分析。分析方法采用了Poisson分布、负两项分布、Neyman分布的频次比较模型和聚合度指数测定以及Taylor指数和 Iwao's 方程模拟。结果表明这三个建群种均符合聚集分布。荔枝(Litchi chinensis )和山杜英(Elaeocarpus sylvestris)两种群有基本型聚集分布的特点并表现出个体间的聚集现象。橄榄(Canarium album)有可能随着密度的增大而趋于均匀分布。树种的空间分布格局依赖于其繁殖特性之外,还受该次生季雨林保护的影响。这些主要建群种的空间格局表明进行该林区保护的迫切性。  相似文献   

5.
We describe patterns of buttress formation and development in eleven tree species at Lawachara National Park, Bangladesh. Fortyfive percent of trees of these 11 species had buttresses. Artocarpus chaplasha Roxb. showed maximum (87%) buttress formation, whereas Alstonia scholaris (L.) R. Br. did not show any buttress. Buttresses were recorded in 20% 40% of trees of six species and 40% 60% of trees in three species. Mean length and height of buttress varied among the species and ranged from 0.37 1.37 m and 0.71 2.13 m, respectively. Buttress height, mean buttress length, total buttress length, and total length pluslength of secondaries increased with DBH (diameter at breast height) and tree height. Buttress number did not increase with DBH or tree height.Under-storey and mid-canopy trees produced less developed buttresses than did emergent trees (p<0.01). Wood density showed moderate effects on buttress characters (p<0.05), while the slope of the land did not. Canopy category was a primary regulating factor for tree buttressing, suggesting that buttresses are mechanical adaptations of trees to counter physical stresses.  相似文献   

6.
This study was designed to answer questions about the patterns of understory diversity in managed forests of southern New England, and the factors that appear associated with those patterns. At the landscape-level, we used plot data to answer questions regarding the spatial distribution of forest understory plant species. Data from a combination of fixed area (understory vegetation) and variable radius (overstory trees) plot methods are combined with site variables for the analysis. Univariate and multivariate statistical methods are used to test for understory diversity relationships with overstory cover types and topography separately, and in combination. Analyses also test for relationships between specific understory species and cover types. In general the understory flora is dominated by four common clonal species that occur across the range of forest cover types: wild sarsaparilla (Aralia nudicaulis L.), Canada mayflower (Maianthemum candense Desf.), star flower (Trientalis borealis Raf.), and partridgeberry (Mitchella repens L.). Results also show that over story composition and structure can be used to assess understory species richness. Species richness follows a general trend among cover types of: hardwood ≥ regenerating forest, hardwood–pine, and pine ≥ mixed ≥ hardwood–hemlock > hemlock. Eastern hemlock (Tsuga canadensis L. Carriere) and mountain laurel (Kalmia latifolia L.) (which decreased in dominance from ridge to valley) both showed negative trends with understory species richness. Topographic position also appears associated with understory floristic patterns (particularly for the hardwood cover type), both in terms of species richness and compositional diversity which both increased from ridge, to midslope, to valley. However, overstory composition (covertype) appears to have a higher order influence on vegetation and mediates the role of topography. The results from this study provide foresters with a better understanding for maintaining floristic diversity and composition of the understory in managed forests.  相似文献   

7.
通过87个样地的调查研究表明,黄桑国家级自然保护区的主要植物群落有:栲林、木荷林、亮叶水青冈林、石栎林、华榛林、鹅掌楸林、桦木林、枫香林、华南五针松林、润楠林、马尾松林、杉木林、闽楠林、云山白兰林、三尖杉林、龙胜杜鹃林、映山红灌丛、竹林、马兰灌草丛等。植物群落景观具有明显的垂直性分布:海拔1 200 m以下为常绿阔叶林带;海拔1 200~1 400 m之间为常绿与落叶阔叶混交林(包括针阔叶混交林);海拔1 400~1 700 m之间为山顶矮林;海拔1 700 m以上为中山灌丛、草丛带。植物群落物种多样性与群落结构的复杂性呈正相关,各群落类型物种多样性指数普遍较高。  相似文献   

8.
Lang C  Polle A 《Tree physiology》2011,31(5):531-538
Knowledge is limited about whether root nutrient concentrations are affected by mixtures of tree species and interspecific root competition. The goal of this field study was to investigate root nutrient element concentrations in relation to root and ectomycorrhizal (EM) diversity in six different mixtures of beech (Fagus sylvatica), ash (Fraxinus excelsior) and lime (Tilia sp.) in an old-growth, undisturbed forest ecosystem. Root biomass and nutrient concentrations per tree taxon as well as the abundance and identity of all EM fungi were determined in soil cores of a volume of 1 L (r=40 mm, depth=200 mm). Stand-level nutrient concentrations in overall root biomass and H' (Shannon-Wiener diversity) were obtained by pooling the data per stand. At stand level, Shannon H' for roots and aboveground tree species abundance were correlated. H' for roots and EM fungi were not correlated because of the contribution of ash roots that form only arbuscular mycorrhizal but no EM associations. Nutrient element concentrations in roots showed taxon-related differences and increased in the following order: beech?≤?lime?相似文献   

9.
Terrestrial ecosystems represent a major sink for atmospheric carbon (C) and temperate forests play an important role in global C cycling, contributing to lower atmospheric carbon dioxide (CO2) concentration through photosynthesis. The Intergovernmental Panel of Climate Change highlights that the forestry sector has great potential to decrease atmospheric CO2 concentration compared to other sectoral mitigation activities. The aim of this study was to evaluate CO2 sequestration (CO2S) capability of Fagus sylvatica (beech) growing in the Orfento Valley within Majella National Park (Abruzzo, Italy). We compared F. sylvatica areas subjected to thinning (one high-forest and one coppice) and no-management areas (two high-forests and two coppices). The results show a mean CO2S of 44.3 ± 2.6 Mg CO2 ha?1 a?1, corresponding to 12.1 ± 0.7 Mg C ha?1 a?1 the no-managed areas having a 28% higher value than the managed areas. The results highlight that thinning that allows seed regeneration can support traditional management practices such as civic use in some areas while no management should be carried out in the reserve in order to give priority to the objective of conservation and naturalistic improvement of the forest heritage.  相似文献   

10.
以野外实地调查、标本采集和文献资料分析相结合的方法,对金洞国家森林公园藤本植物的资源种类、区系地理成分、生态特征及园林应用进行了系统研究。结果表明:(1)该区藤本植物共计有48科107属238种(含变种),科种数分别占该区维管植物科、种的22.86%、15.29%,其中蕨类植物有2科2属2种,双子叶植物43科101属212种,单子叶植物3科4属24种。(2)该区植物区系成分复杂,以热带性分布为主,其中泛热带分布最多,占到了属总数的25%,出现了海南链珠藤、大花帘子藤等严格热带区系成分的藤本。(3)该区缠绕类藤本占优势,共计110种,占总数的46.22%,卷曲类、搭靠类、吸固类种类较少,分别占总数的24.79%、19.33%和9.66%。(4)该区观赏性藤本植物有较多种类,通过在长沙的引种试栽与观察,重点推荐中南鱼藤、粉叶羊蹄甲等32种具有一定观赏价值的藤本植物作为城市园林绿化应用参考。  相似文献   

11.
In this article, we present equations derived for the prediction of the aboveground tree volume and phytomass for twenty-five of the most important forest species growing in Italy. These equations result from ongoing research aiming to fill a gap in the models available at the national scale. With regard to volume, the results are particularly important for thirteen species or groups of species that were once scaled with models, conventionally assumed as reference models, available for other species. In Italy, phytomass models had never been constructed at the national level before. For any single tree, specific equations allow estimations of the following tree components to be made: stem and large branches (for either volume or phytomass), small branches (phytomass), stump (phytomass) and the whole tree phytomass. The models have been constructed on the basis of nearly 1,300 sampling units (sample trees). Although these equations must be considered intermediate results of the ongoing research because only half the scheduled number of samples has been collected, they have already been used in the practice, for example in the estimates reported in the recently published second national forest inventory.  相似文献   

12.
森林树种生物多样性的保护是当代全球关切的问题之一。要保存森林资源,也就要保存森林物种,更重要的是保存构成森林主体的树木。而要保存树种,首先要保存树种内性状的多样性,因为种内多样性消失是物种消失的先导。同名性状多样性,是决定或控制同名性状的等位基因决定的,因此与保存多种多样的基因资源联系在一起。现就森林树种生物多样性保护与遗传学中的变异等理论关系作以简述。1 生物多样性和森林树种资源 生物多样性是人类赖以生存的各种有生命资源的总汇和未来工农业、医药业发展的基础,为人类提供了食物、能源、材料等基本需…  相似文献   

13.
上海海湾国家森林公园景观林优化改造   总被引:1,自引:3,他引:1       下载免费PDF全文
在对海湾国家森林公园景观林资源现状调查分析的基础上,根据公园即将向公众开放对林木景观资源的质量和标准要求,针对存在主要问题,提出相应的优化改造措施。通过对本公园人工幼龄林培育过程中,出现的林相单调,密度过大有碍森林赏景、影响森林生态效益的发挥及阻滞森林健康演替等问题提出相应的改造措施,旨在优化提升森林美学等级。    相似文献   

14.
以天童国家森林公园常绿阔叶林主要组成树种为研究对象,通过测定其各组分生物量,建立了实测生物量与材积之间的回归模型,结果表明:主要组成树种各组分生物量与其材积之间存在着密切的相关关系,各主要树种材积与生物量的回归模型存在差异;回归方程精度较高,用于根据地区常绿阔叶林主要树种材积推算其生物量是可行的。  相似文献   

15.
  • ? Understanding the effects of tree species diversity on biomass and production of forests is fundamental for carbon sequestration strategies, particularly in the perspective of the current climate change. However, the diversity-productivity relationship in old-growth forests is not well understood.
  • ? We quantified biomass and above-ground production in nine forest stands with increasing tree species diversity from monocultures of beech to stands consisting of up to five deciduous tree species (Fagus sylvatica, Fraxinus excelsior, Tilia spp., Carpinus betulus, Acer spp.) to examine (a) if mixed stands are more productive than monospecific stands, (b) how tree species differ in the productivity of stem wood, leaves and fruits, and (c) if beech productivity increases with tree diversity due to lower intraspecific competition and complementary resource use.
  • ? Total above-ground biomass and wood production decreased with increasing tree species diversity. In Fagus and Fraxinus, the basal area-related wood productivity exceeded those of the co-occurring tree species, while Tilia had the highest leaf productivity. Fagus trees showed no elevated production per basal area in the mixed stands.
  • ? We found no evidence of complementary resource use associated with biomass production. We conclude that above-ground productivity of old-growth temperate deciduous forests depend more on tree species-specific traits than on tree diversity itself.
  •   相似文献   

    16.
    不同森林类型物种多样性及影响因子研究   总被引:2,自引:0,他引:2  
    采用丰富度指数、多样性指数、均匀度指数对雾灵山不同森林类型灌木层和草本层的物种多样性进行了研究,并在此基础上用逐步回归方法研究影响森林物种多样性的主要因子。结果表明,在不同森林类型中灌木层和草本层物种多样性由高到低依次为:针阔混交林>落叶阔叶林>针叶林;多数森林类型草本层丰富度指数和多样性指数均高于灌木层,而均匀度指数则相反。影响灌木层物种多样性的主要因子包括林龄、郁闭度和坡向,影响草本层物种多样性的主要因子包括林分公顷株数、郁闭度和土层厚度。  相似文献   

    17.
    An increased understanding of the importance of forest diversity for ecosystem services such as medicine, wood, climate control, etc., has lead to greater interest in the study of forests. This study aims to analyze the diversity, composition, and distribution pattern of tree species in Pachamalai Reserve Forest in the Eastern Ghats of Tamil Nadu State. Data were collected in the quadrant method, where 10 × 10 m2 plots at different altitudes from 230 to 930 m with 50-m regular intervals were plotted. A total of 73 tree species belonging to 35 families with the density of 1,372 individuals were enumerated from 3 ha. Overall, the most dominant tree species family was Fabaceae (21 species). The highest number in terms of density of tree species was observed for Pongamia pinnata and the most dominant on the basis of basal area was Tamarindus indica. The species inventory was calculated by Shannon-Weiner index (3.916), Simpson index (0.0206), and Margalef index (9.9667). With the increasing altitudinal gradient, the maximum species richness was observed in the middle elevation zone from 580 to 780 m. The results from the study could be helpful for monitoring and sustaining the forest resources, and important in preventing the loss of biodiversity and mitigating climate change.  相似文献   

    18.
    薛煜  包立新  李淳 《林业研究》1996,7(3):19-22
    INTRODUCTIoNSSPCCiesdiversityistheoneofthreekcysubjcctS(Theglobalweatherchange,speiesdiversltyandsustainedecologysystem)inccologicalandenvironmentalscienceinrecenttenyears.Williams(I943)firstputfonvardsPecicsdiversitywhenhestUdiedtherelationbctx`centhcabundanccandinsectspecicsofLcl,i`mptcra.In6()'s~7()'s-ccologicaIscicn-tistshadgotagreatofachicvementsonsPCcicsdlt'crslti'stud\.Sinccl98()-s.somcscientistsstartcdtostud}'sPCcicsdivcrsityinCl1ina.Thcy'havcgotsolnercsultsol1artl1roPOdcom…  相似文献   

    19.
    从森林生态旅游发展趋势出发,结合塞罕坝国家森林公园森林旅游发展现状,分析了该公园森林生态旅游的内涵,提出了加快发展其生态旅游的策略。  相似文献   

    20.
    Four forest stands each of twenty major forest types in sub-tropical to temperate zones (350 m asl–3100 m asl) of Garhwal Himalaya were studied. The aim of the study was to assess the stem density, tree diversity, biomass and carbon stocks in these forests and make recommendations for forest management based on priorities for biodiversity protection and carbon sequestration. Stem density ranged between 295 and 850 N ha−1, while total biomass ranged from 129 to 533 Mg ha−1. Total carbon storage ranged between 59 and 245 Mg ha−1. The range of Shannon–Wiener diversity index was between 0.28 and 1.75. Most of the conifer-dominated forest types had higher carbon storage than broadleaf-dominated forest types. Protecting conifer-dominated stands, especially those dominated by Abies pindrow and Cedrus deodara, would have the largest impact, per unit area, on reducing carbon emissions from deforestation.  相似文献   

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