Societal change and the control of deforestation in Thailand

Thailand underwent a major shift in forest policy in the second half of the 1980s to promote sustainable management and control of deforestation. This paper puts this in the context of earlier changes in forest policy and analyses the underlying causes of the shift by analysing changes in the relative strength of different interest groups within the framework of a policy pressures model. Internal pressures had a stronger impact on Thai forest policy than external pressures. Protectionist groups became more numerous and more powerful in Thailand in the 1980s in relation to exploitative groups, and their rise in influence was facilitated by continuing progress in democratization and pluralization, linked to the consequences of economic development. Such political change could help to explain the apparent link between better environmental management and economic development shown in the Environmental Kuznets Curve.     

Indigenous uses and structure of chir pine forest in Uttaranchal Himalaya,India

The various indigenous uses and structure of chir pine forests were studied in Uttaranchal state of the Indian Republic. A questionnaire survey was conducted in 50 villages of Uttaranchal to gather information on the indigenous uses of chir pine. For the study of community composition and structure of chir pine forest, at least 15 quadrats of 10 x 10 m were selected randomly across various localities, and the number of individuals, along with other dominant tree and shrub species, were enumerated in each quadrat. About 10 indigenous uses of chir pine were prominent in Uttaranchal. Besides resin, an important non-wood product, different parts of chir pine, such as cones, trunk, stems, wood, leaves and bark, were used by the local people. Chir pine is a subject of the folklore and mythology of indigenous cultures in Uttaranchal. Chir pine forest formed three major communities in Uttaranchal viz., sal-pine (Shorea robusta-Pinus roxburghii), pine pure stands and oak-pine (Quercus leucho-trichophora-Pinus roxburghii). These communities sustained various multiple-use trees and shrubs along with various edible mushrooms (eg. Agaricus campestris, Morchella esculenta and Sparassis crispa). The results of this study are discussed in the light of chir pine conservation and management policies.     

Assessment of the erosion control function of forest ecosystems based on GIS: a case study in Zhangjiajie National Forest Park,China

Erosion control is one of the most important functions of forest ecosystems, and its accurate assessment is useful to illuminate the importance of forest ecosystem services for humans so as to rationally conserve forest resources. This paper examines Zhangjiajie National Forest Park, the first national forest park in China, to seek practical methods for assessment of the forest erosion control function using a geographical information system (GIS). The results show that the potential and actual amounts of soil erosion are 2.92 million ton and 0.14 million ton per year, respectively, in Zhangjiajie National Forest Park. The total reduction in soil loss reaches 2.77 million ton per year with the existence of a forest ecosystem. The erosion control function of near mature, mature and over mature broadleaf forest is excellent, and natural forest conservation and natural restoration of the degraded forest ecosystem can provide the largest benefits in soil erosion control. Nearly all the near mature, mature and over-mature forest in the park is at the top and in steep mountain areas, and could be rationally cut and utilized by local communities, but extensive timber felling should be strictly prohibited.     

The archaeology of deforestation in south coastal Turkey

The Rough Cilicia Archaeological Survey Project investigates landscape transformation as a component to its regional survey of ancient Rough Cilicia (south coastal Turkey opposite Cyprus). Rough Cilicia was celebrated during antiquity for pristine cedar forests that stood between 1500 and 1800 m in altitude along the slopes of the Taurus Mountains. Today along the front range of the Taurus Mountains this forest is completely denuded or otherwise replanted with recent growth in the past 80 years. We employ paleoenvironmental analysis of relic cedar forests in the Taurus Mountains to construct a timeline of anthropogenic disturbances associated with population growth over time and thereby assess the sustainability of ancient forestry practices. To obtain these data, the team recovers pollen and carbon samples from geomorphologic trenches excavated in the cedar zone, tree ring data from dendrochronological survey of the existing forest, and archaeological data from remains of ancient highland settlements. Preliminary results indicate that current perspectives about the timing of deforestation in this region are flawed and that the initial deforestation coincided with regional site abandonment and population decline at the end of antiquity.     

季风常绿阔叶林演替系列菌根资源及其与群落多样性的关系

随着森林生态系统的正向演替,植物物种多样性、群落结构、生产力以及土壤条件均会发生显著的变化,这些变化对菌根类型和多样性会产生不同程度的影响。为了探讨群落结构和功能的变化对菌根资源可能产生的影响,选择季风常绿阔叶林及其演替系列上的代表性森林生态系统为对象,对菌根化根系、菌根类型和菌根真菌孢子密度进行调查,并结合已有的群落信息和土壤养分状况,分析在森林演替过程中菌根资源的变化情况和可能的影响因素。结果表明:季风常绿阔叶林各演替阶段的森林生态系统中菌根化比例接近70%,但不同演替阶段森林的优势菌根类型存在明显的差异。处于演替初期的马尾松(Pinus massoniana)林以丛枝菌根为主,占菌根总数的78%;演替中期的针阔叶混交林中的外生菌根占有绝对优势,占75%,是丛枝菌根的3倍;演替顶级的季风常绿阔叶林中的外生菌根和丛枝菌根的比例相当。马尾松林的菌根真菌孢子密度最高,每20 g风干土壤中的孢子数量高达2 925个,是针阔叶混交林的2.5倍,季风常绿阔叶林的2倍。演替系列上的森林生态系统的菌根类型的差异与植物物种多样性和群落结构,尤其是林下的灌木、草本层密度存在一定的相关性,同时也受土壤养分状况的影响。马尾松林具有较丰富的草本植物和较高的草本层密度,并且该森林的土壤相对贫瘠,这些条件都有利于丛枝菌根真菌侵染草本植物的根系形成丛枝菌根并产生大量孢子。针阔叶混交林中外生菌根的优势主要受该森林中外生菌根植物在群落组成上的绝对优势影响。季风常绿阔叶林的物种丰富,群落结构复杂,因此该森林呈现了两种类型菌根优势相当的现象。该文的结果表明,随着季风常绿阔叶林演替的进行,菌根资源在类型上会出现较大的分异,而这种变化受植物物种数量、群落结构的影响,与土壤养分状况存在一定的关系,并且不同演替阶段森林生态系统影响菌根组成的因素存在差异。     

大兴安岭南部温带山杨天然次生林不同生长阶段生物量及碳储量

基于内蒙古赛罕乌拉森林生态系统定位研究站山杨（Populus davidiana Dode）天然次生林幼龄林、中龄林、近熟林、成熟林及过熟林生物量调查,探讨了不同龄组山杨天然次生林单株木、林分、林下植被和枯落物的生物量及群落碳储量的时空变化规律。结果表明：随林龄的增大,山杨天然次生林木和各器官生物量总体呈增加趋势,树干所占比例增加,中龄林增加尤为明显;林下植被层、枯落物层生物量随林龄增大呈增加趋势。群落总碳储量的空间分布序列是：乔木层〉枯落物层〉林下植被层。幼龄林、中龄林、近熟林、成熟林和过熟林群落的碳储量分别为27.146 6、53.545 1、60.889 8、77.915 8、79.135 3t.hm-2,乔木层碳储量分别为22.206 5、47.215 7、52.056 3、68.445 3、68.773 1 t.hm-2,枯落物层和林下植被层碳储量平均值分别为5.814 4、2.172 7 t.hm-2。乔木层、枯落物层和林下植被层碳储量占总量的平均率分别为86.05%、10.39%和3.57%。研究认为山杨天然次生林群落碳储量随林龄增加的变化规律明显,碳汇潜力巨大;中龄林为碳储量增长迅速期,且持续较长一段时间,是林分管理的关键阶段;自然稀疏有利于促进林木生长,林分碳储量并未随林分密度下降而减小。     

森林土壤氧化（吸收）甲烷研究进展

甲烷是一种重要的温室气体,对全球气候变暖的贡献仅次于CO2,约为25%。大气甲烷可以被土壤中甲烷氧化细菌在有氧条件下吸收利用,陆地生态系统森林土壤氧化吸收甲烷的研究已有大量报道。甲烷氧化菌是以甲烷作为唯一的碳源和能源的一类细菌的总称。但森林土壤在全球甲烷核算中具有一定的不确定性,取决于产甲烷菌和甲烷氧化菌的相对活性。甲烷氧化菌的研究集中在环境对氧化能力的影响和自身氧化能力上。大气甲烷氧化过程为高氧化能力低亲力氧化,受到一些因子,如土壤温度、土壤通气状况、pH、氮肥等的影响,具体机理的研究还有待进一步深入。土壤通气状况受土壤质地与土壤水分影响,土地利用类型可能改变土壤容重、土壤结构和土壤水分,进而影响土壤甲烷氧化。植物可以通过自身对生境的作用或化感作用影响土壤甲烷氧化。土壤动物的研究则相对较少,目前排放清单中仅有白蚁是全球甲烷核算所包括的。从甲烷氧化菌的分类出发,对甲烷氧化菌氧化甲烷的机理、菌的生态分布及甲烷氧化的影响因素、时空异质性、观测方法等作出了综述,为正确认识和准确预测森林土壤在一定气候和土地利用类型条件下的甲烷氧化强度提供理论依据。     

冻融对长白山森林土壤碳氮矿化的影响

长白山地区秋末春初常常存在冻融过程,冻融过程影响土壤水分分布而改变土壤理化性质。通过室内模拟实验,研究了冻融过程（-20~15℃）对长白山阔叶红松（Pinus koraiensis）林和白桦（Betula platyphylla）林土壤有机碳和氮矿化过程的影响。结果表明,经过3次冻融循环,冻融处理土壤矿化速率显著高于对照处理,但经过多次冻融循环过程,冻融处理抑制土壤有机碳矿化过程,对照处理土壤有机碳矿化速率高于冻融处理（P=0.019）。在培养结束后,冻融处理的阔叶红松林和白桦林土壤无机氮质量分数,分别是对照处理的1.88倍和1.96倍;冻融次数也是影响土壤有机氮矿化的一个重要因素,35次冻融循环后,阔叶红松林和白桦林土壤中无机氮分别提高了2.10倍和2.81倍。冻融循环促进了土壤有机氮的矿化,有利于土壤中有效氮的累积,为春季植物生长提供足够的氮素,但也潜在增加了土壤中无机氮流失的风险。     

上海、北京和天津碳排放的比较

以北京、天津、上海为例,探讨了城市碳排放趋势预测的研究方法。采用最优增长率模型,研究了经济平稳增长的条件下,各市未来的能源碳排放趋势。考虑了水泥工业的碳排放量,并采用CO2FIX模型计算各市森林碳汇量,从而得到各市净碳排放量。结果表明：北京、天津、上海的能源碳排放量都呈倒U型曲线,上海的碳排放量远高于北京和天津两市。北京、天津、上海的水泥碳排放量都呈增加趋势,其中北京每年的水泥碳排放量最大,且增长率也是3个城市中最大的。北京和天津的累计森林碳汇量不断上升,上海的累计森林碳汇量几乎为零。北京、上海、天津的净碳排放量仍呈倒U型曲线增长,但与不考虑水泥碳排放和森林碳汇时的情况差别不大。由此可见,北京、上海、天津应重点减少能源碳排放,有效控制水泥产业碳排放,逐步扩大植树造林面积,从多方面采取措施降低碳排放。     

林场管理经济效益提升方法分析

林场管理经济效益提升需要从具体工作做起,需要落实好国家相关政策,充分利用林业资源,坚持走林场产业化发展道路,把林场生态资源分配好,优化各种产业链条,推动林场管理水平不断提高。我国林场管理工作是一个长期的过程,需要做好科学管理、技术管理工作,需要制定符合林场发展的总体规划,推动林场管理经济效益不断提升,促进林场各项工作可持续发展。