黑杨派南方型无性系高生长与气候条件的斜率关联度分析

用灰色系统理论的斜率关联度分析法，求得影响黑杨派南方型无性系高生长的主要气候因子依次为：降水量、极低温、极高温、蒸发量、日照时数、积温、年均温（或相至湿度）、相以湿度（或年均温）、无霜期。     

午潮山常绿阔叶林气候生态效应定位研究

午潮山常绿阔叶林气候生态效应，经过８年（１９８８￣１９９５）定位观测研究，取得了若干规律性数据，加深了对常绿阔叶林生态系统气候生态学特征的认识，为持续经营、保护、利用和发展常绿阔叶林，提供了一定的科学依据。文中较系统地论述了午潮山常绿阔叶林的日照、温度、湿度，林内降水量再分配，酸雨等问题。     

气候变化对中国东北地区生态与环境的影响

【研究目的】综述了气候变化对东北地区的影响,以期在区域发展中能利用气候变化的有利方面,降低其不利的影响;【方法】根据近年来发表的相关论文,文章综述了东北地区已经发生的气候变化影响及未来可能受到的影响;【结果】结果表明,过去100年东北地区的温度升高明显且降水普遍减少,干旱化趋势严峻。温度的升高改善了东北的热量资源,部分农业生产从中受益。但由于气候变化,目前特殊的生态系统如湿地,冻土退化或消失。未来的气候变化,会改变农业生产布局,降低主要作物的产量,生态系统结构发生改变,农牧带沙漠化的风险增加;【结论】东北地区必须客观认识气候变化的利弊影响,采取相应的适应和应对措施,促进区域发展。     

气候变化下子午沙鼠在中国的潜在分布分析

为探究气候变化下子午沙鼠在中国的潜在分布和时空变化,本研究利用子午沙鼠分布数据以及气候、地形等环境数据,基于最大熵模型(The maximum entropy,MaxEnt)和地理信息系统(Geographic information System,GIS)技术,分析大空间尺度上限制子午沙鼠地理分布的主导环境因子。结果表明：当前气候下子午沙鼠高适生区主要分布在甘肃河西走廊、内蒙古西南部、宁夏北部,以及新疆塔里木盆地和天山山脉之间、伊犁州和塔城等地区,中适生区主要分布在甘肃酒泉的北部,内蒙古西北部,青海中部以及新疆的大部分地区;温度是限制子午沙鼠分布的主导气候因子,其次是海拔,降水量也有一定影响。随着全球气候变暖,子午沙鼠生境适宜度提高,在中国的潜在分布范围将扩大。本研究对子午沙鼠危害监测预警和精准防控具有重要的指导意义。     

Forest soils and carbon sequestration

Soils in equilibrium with a natural forest ecosystem have high carbon (C) density. The ratio of soil:vegetation C density increases with latitude. Land use change, particularly conversion to agricultural ecosystems, depletes the soil C stock. Thus, degraded agricultural soils have lower soil organic carbon (SOC) stock than their potential capacity. Consequently, afforestation of agricultural soils and management of forest plantations can enhance SOC stock through C sequestration. The rate of SOC sequestration, and the magnitude and quality of soil C stock depend on the complex interaction between climate, soils, tree species and management, and chemical composition of the litter as determined by the dominant tree species. Increasing production of forest biomass per se may not necessarily increase the SOC stocks. Fire, natural or managed, is an important perturbation that can affect soil C stock for a long period after the event. The soil C stock can be greatly enhanced by a careful site preparation, adequate soil drainage, growing species with a high NPP, applying N and micronutrients (Fe) as fertilizers or biosolids, and conserving soil and water resources. Climate change may also stimulate forest growth by enhancing availability of mineral N and through the CO₂ fertilization effect, which may partly compensate release of soil C in response to warming. There are significant advances in measurement of soil C stock and fluxes, and scaling of C stock from pedon/plot scale to regional and national scales. Soil C sequestration in boreal and temperate forests may be an important strategy to ameliorate changes in atmospheric chemistry.     

民勤沙区降水及干旱特征分析

民勤干旱沙区降水稀少，３４年年平均降水量为１１３．２ｍｍ，且季节分布不均，年际变化大，平均降水变率为２４．５％，降水年变化规律呈正态分布。降水性质多以日降水量≤１０．０ｍｍ的小雨为主。持续干旱日数长，发生频率高，属典型干旱荒漠气候。     

An AHP Assessment Of Barriers in Adopting Sustainable Forest Management Practices in The Context Of Carbon Emission Reductions in Cameroon

ABSTRACT

As the role of forests in climate change mitigation is explicitly recognized in the Paris Agreement, the need to enhance the adoption of Sustainable Forest Management (SFM) practices is crucial. Therefore, this paper aims at identifying and evaluating barriers in adopting SFM practices in the context of forest carbon emission reductions. A total of 15 barriers in adopting SFM practices are listed through literature and expert inputs. Using Cameroon as a case study, the listed barriers are then evaluated by experts to determine their relative importance using the Analytical Hierarchy Process (AHP) method. According to our findings, the ‘Regulatory and Legislative frameworks’ barrier category was attributed to the highest importance among other categories, in adopting SFM practices in the forestry sector. ‘Inadequate political will and incentive to enforce regulations’ appears to be the major obstacle in adopting SFM practices in Cameroon. As carbon emission reduction initiatives are being developed, there is need to move from broad to concrete suggestions that will overcome these barriers. However, proper diagnosis is necessary in order to target barriers with the right incentives and enabling conditions that will support carbon programs and projects to deliver effective emission reductions.     

Simulating responses of Northeastern China forests to potential climate change

IntroductionItissurethatpresentelevatiollsofCO2a11dotllergrcc11-housegasesinducedbyhumanactivitiesaren1akli1gglobalclimategothroughinexperielICedcl1anges(Scl1le-subgerl987).Thecurrentquasi-equilibriulllstatesofbio-sphereecosystCm,esPeciallyterrestrialecosystems,wouldbebrokenbecausetl1estructure,fu11ction,distributio11andtlledynamicsofanyexistedecosystemsareIberesultsoflongtermadaptationofbio-systemtocurrentclin1ate.Theec()systemsdistributedinhighlatitlldeareawouldhavemuchbiggerchai1ge(Bona…     

Using model scenarios to predict and evaluate forest-management impacts on soil base saturation at landscape level

Silviculture, forest conversion and technical tools of ecosystem management, such as forest liming, display their effects at the landscape level. Therefore their planning and control should take place at the same scale. The primary objective of this work was to assess soil chemical properties and their changes in relationship to ecosystem management, especially forest conversion and forest liming. We calculated scenario models, based on regression analysis, which allow such an examination in the context of understanding landscape processes which can be expected to operate in the sampling region. Stepwise multiple linear regression analysis was used to predict soil chemical attributes (base saturation, pH, C/N content and stock, exchangeable stocks of Ca and Mg) as indicators of site stability or off-site effects of forest ecosystems such as effects on clean drinking water from forested watersheds. Because of space limitations, in this paper only the modelling results of base saturation are presented. Base saturation was used as an integrative example for other soil chemical properties. The transformation of measurements to the regional scale, i.e., the regionalization, was calculated for the forested parts of two test regions in the Black Forest on the basis of measured chemical properties of 90–150 soil profiles per test region. The models have a spatial resolution of 50×50 m, which is a spatial scale relevant for forestry practice and forest management. Topographic variables (e.g., elevation, aspect, slope gradient, and slope length), the stratigraphic classification of the geologic substrate, stand characteristics from forest inventory data, and finally technical information about forest liming were the auxiliary variables (secondary site properties) that provided indirect information about base saturation and were available for the whole forested area of the test regions. Base saturation could be predicted with an accuracy of ~50–70% (in terms of the multiple R²) by using these properties as predictor variables in multiple linear regression analyses. The explained proportion of variance was unexpectedly high considering the high geomorphological heterogeneity of the two test regions. Based upon the regionalization models, it was possible to establish scenarios showing the landscape-related effects on base saturation that may be achieved by forest conversion towards a higher proportion of forests with broad-leaved mixed stands and by forest liming. These scenarios allow the interactions between several influencing factors and management strategies and the impacts on the target variable to be synoptically judged. Thus the presented regionalization models achieve the role of decision support tools for the planning of forest management at the landscape level. They allow an assessment of the environmental effects of forest management strategies in terms of site sustainability or preservation of water resources in forested catchments.     

火干扰与气候因子对兴安落叶松径向生长的影响

火干扰对森林生态系统的稳定具有重要影响。以1987年5月森林火灾后的漠河林区为研究对象,按照不同的林火强度设置样地,在不同强度火干扰样地内,分别采集兴安落叶松(Larix gmelinii(Rupr.) Kuzen)的树轮样芯,建立树木年轮的宽度年表,分析不同强度的火干扰及气候对兴安落叶松径向生长的影响。结果表明:(1)不同强度火干扰对落叶松径向生长影响程度不同,轻度火干扰样地落叶松生长存在胸径加速生长期,重度火干扰样地落叶松生长存在胸径减速生长期。(2)轻度火干扰样地落叶松年轮宽度与前一年7月份和当年7月份降水量呈显著正相关(P<0.05),与前一年9、11月份和当年9月份最高气温呈显著正相关(P<0.05);重度火干扰落叶松年轮宽度与前一年7月份和当年7月份最高气温呈显著负相关(P<0.05)。(3)不同强度的火干扰对年轮宽度和气候因子的相关性影响不同,重度火干扰样地落叶松年轮宽度与气候因子的相关关系在火干扰前后的变化比轻度火干扰更加明显;该地气温过度升高不利于重度火干扰后落叶松的恢复,而对轻度火干扰后落叶松的径向生长的影响不显著。