Hydrochemical Fluxes and their Effects on Stream Acidity in Two Forested Catchments in Central Scotland

The hydrochemical fluxes and budgets have been determined fortwo forested catchments, including inputs, tree throughfalland stemflow, soil water throughflow and output streams. Themajor vegetational induced differences are the enrichment ofsodium, chloride, sulphate and particularly hydrogen by Sitkaspruce compared to Norway spruce. These increased concentrationsare primarily due to vegetation interception along with crownleaching, both of which contribute to sulphate enhancement.Soil throughflow and consequent stream chemistries reflect thesespecies effects with additional enrichment both due to geologicalweathering of base cations as well as possible desorption ormineralization processes. Norway spruce vegetation and the associatedpodzolic soils show no net stream acidification (pH 4.61) ofinputs (pH 4.65), whereas Sitka spruce on gleyed soils showconsiderable stream acidification (pH 4.02) compared with similarinputs (pH 4.50). Both streams have similar sulphate concentrations,but this important mobile anion is associated primarily withhydrogen in the Sitka spruce dominated Kelty catchment whereasat Chon it is associated with base cations as well as hydrogen.     

Concentrations of Cadmium,Lead and Mercury in Different Soils in Two Swedish Forest Catchments

Accumulation of cadmium (Cd), lead (Pb) and mercury (Hg), as affected by organic matter content, pH of different soil compartments and the physicochemical properties of each metal, was studied in different soil types within two forested catchments of the Norway spruce (Picea abies - Vaccinium myrtillus) type. Independent of soil type, the highest metal concentrations were found in the organic layers of the soil, usually in the surface soil. The concentrations in the upper part of the mineral subsoil were about one-fifth to one-tenth, or less, of those in the organic surface soil. Concentration maxima in the B-horizon were more pronounced for Cd and Hg than for Pb. When comparing soil types, the highest concentrations of Cd were found in the less acidified fens in the discharge area, while for Hg and Pb the highest concentrations usually occurred in the mor layer of the well-drained Podzols. For all metals, the soil types with the largest accumulation had concentrations up to 2-3-fold higher in the organic layers than those with the smallest accumulation.     

青山白化问题及其治理

阐述了青山白化问题存在的危害性及其根源，提出了治理青山白化要从思想上加以认识、政策法律上加以规范、管理上加以配套服务的一系列具体措施。     

Contrasting Hydrological Regimes in Two Ploughed Forest Soils in Upland Wales

Contrasting hydrological regimes in a cambic stagnohumic gleyand an ironpan stagnopodzol were monitored at the Tywi Forest,Mid-Wales, during the hydrological year 1988–1989. Variationsin the hydrological behaviour of each soil were observed inrelation to hillslope topography and the localized influenceof plough furrows and planting ridges. High rooting densitiesin the well-structured O horizon of the stagnohumic gley encouragedlateral seepage above the relatively impermeable subsoil andconcentrated summer drying in the surface horizons. Marked subsoildrying appeared to be related to deeper root penetration whereunsaturated subsoil conditions prevailed in upslope areas orbeneath planting ridges. In contrast, the ironpan stagnopodzoldid not have impeded drainage due to structural features andthe roots penetrating the E horizon and ironpan. Moreover, thesubsoil was coarsely textured and freely draining. Consequently,rooting was more extensive and hydrological regimes were moreuniform and not simply related to topography. Soil disturbanceand extensive root penetration in plough furrows appears topromote preferential water movement during storm events andcreate drier summer soil conditions.     

长春——北方第一座森林城

长春"森林城"是我国北方内陆城市的一张名片。先后被评为"全国造林绿化先进单位"、"全国园林绿化先进城市"、"全国造林绿化十佳城市"、"全国造林绿化最佳城市"、"环境综合治理先进城市"、获"全国人居环境范例奖"。       

Stream Flow and Afforestation of Water Catchments

Trees in catchment areas are believed to affect the supply ofwater to reservoirs. Increased flooding has been noticed whereextensive modern drainage has been practised. Stream-flow measurementswere recorded over a short period in the headwaters of the Conwayin autumn 1967 and run-off from a recently planted area wasinitially faster than from closed woodland and very much fasterthan from an unplanted (and undrained) site.     

不同气候区4种典型地带性植被土壤水文功能比较

以中国生态系统研究网络长期定位观测的西双版纳热带季节雨林、鼎湖山亚热带常绿阔叶林、哀牢山中山湿性常绿阔叶林和长白山阔叶红松林为基础,分析比较4种森林类型土壤水文功能的差异。研究结果表明:土壤容重随土层深度增加而增大,土壤孔隙度、有效含水范围、饱和含水量和月均含水量随土层深度增加而降低;鼎湖山地表径流量及其占总降雨量的比例最大,哀牢山蒸散量及其占总降雨量的比例最大;4种森林类型0~50 cm厚度土壤最大吸水能力为哀牢山>鼎湖山>长白山>西双版纳,蓄水量则为鼎湖山>长白山>哀牢山>西双版纳。     

占用征用林地管理的有关问题与对策探讨

扼要阐述了当前我国占用征用林地管理的基本现状和存在的主要问题。针对存在的问题,提出了加大执法力度,建立责任追究制度、岗位考核制度、会审制度、审批公示制度、总量控制制度等加强占用征用林地管理的措施。     

刘振华在古交市调研时指出要用好用足用活退耕还林政策

本刊讯　 4月 2 2日 ,刘振华省长在古交市调研城建工作时指出 :“加强生态建设 ,优化投资环境 ,关键是要用好用足用活退耕还林政策 ,找准高速公路、旅游线路、旅游景点和城市周边重点 ,优先考虑 ,率先落实”。从上午 9时开始 ,刘振华先后考察了古交市文华苑教工住宅小区、小泉寨公园、金业煤焦化集团、兴园路桥梁预制工地和市民广场。在水泉寨公园 ,刘振华兴致勃勃地攀上最高点望川楼 ,登临远眺 ,听取古交市城市规划汇报后 ,要求把城市周边尽快绿化 ,动员移民 ,让农民自愿选择 ,能搬则搬 ,不能搬迁的也要美化起来。刘振华在听取了古交市委和…     

林区地形条件对GPS定位精度的影响

在林区周边多种地形中布设试验点,通过实地测量,探讨地形因子对高性能GPS接收机单点定位和GPS-RTK定位精度的影响。研究表明:两种常用的GPS测量方式同一时间段观测值有一定的聚集性,不同时段之间会产生整体性偏差;Trimble 5800 GPS接收机单点定位在不同地形中测量的内外符合精度为0.512~4.465 m,受山体和建筑物的影响较大,较空旷区域中可以达到分米级精度;RTK技术在观测条件较好时,平面中误差大多在1 cm以内,高程中误差为1~3 cm,上午、下午两个时段定位精度相近,在郁闭度较高的林中观测精度较低,只有亚米级,高程精度更低,大多历元得不到固定解,在山谷等更恶劣的地形中,甚至得不到浮动解。     

两种藤本植物叶片性状及相关性对季节的响应

研究通过对两种藤本植物叶片的叶面积、比叶面积、叶厚度、气孔参数和叶脉密度的测定来分析不同季节下植物叶片的性状差异以及其性状之间的联系,为探讨植物叶片性状对环境适应的可塑性提供理论基础,同时也为藤本植物在园林中的应用提供依据。结果表明:(1)两种藤本植物叶片各性状随着季节变化呈现显著差异(P<0.5),季节变化对五叶地锦的影响大于爬山虎。两种植物的叶面积和叶厚度均夏季为最高;五叶地锦叶片气孔长度和气孔密度随季节变化先减小后增大;爬山虎叶片气孔长度随季节变化逐渐增大,气孔密度先减小后增加,春季气孔密度最大;叶脉密度均为春季最大,夏季和秋季逐渐降低。(2)两种植物叶片各性状之间存在一定的联系,但是显著性因品种和季节变化而不同。     

头塘小流域水文特征及不同植被的水文效益分析

根据头塘小流域连续8年(2000～2007)的水文监测数据,分析小流域降雨、径流特性;分析了乔、灌、草结合的生态林地植被恢复模式在2002～2005年的径流系数、泥沙消减率趋势,以经济林地和未退耕林地为对照,比较了三者之间在径流系数与泥沙含量方面的关系.结果表明:小流域径流量与降雨量的变化趋势基本一致,洪枯比连年呈下降趋势;与2002年相比,生态林地径流系数、泥沙含量均有所减少,泥沙消减率比较显著;三者之间径流系数与泥沙含量关系为:生态林地＜经济林地＜未退耕地,表明以生态林地为主的恢复模式在涵养水源、保持水土方面的作用显著.     

两种百合种群空间分布格局对高温干旱气候的响应

将分形分析与方差均值比率及聚集强度指数相结合,比较分析了南川百合与泸定百合种群在高温干旱影响下的空间分布格局及其分形特征.研究表明:分形分析同方差均值比率及聚集强度指数测定得到的结果基本一致,说明分形维数不仅可以很好地反映种群的空间分布格局,也能很好地反映种群动态;两种百合种群的聚集强度均受到2006年高温干旱的影响,但南川百合种群所受影响比泸定百合大;两种百合的平均计盒维数和平均信息维数与2005年相比均减少,但南川百合种群平均计盒维数的减少比例(13.00%)约为泸定百合(9.04%)的1.44倍,平均信息维数的减少比例(22.71%)约为泸定百合(3.43%)的6.63倍,高温干旱天气对这两种百合的生长均有影响,泸定百合的抗热抗旱能力要高于南川百合,南川百合更易受高温干旱天气的伤害.与泸定百合相比,南川百合是一个比较脆弱的物种,在高温干旱等异常气候的影响下更易导致濒危,应尽快加以保护.     

Effects of Forest on the Budgets of Water，Energy and Gases in the Environment

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有林地面积动态变化及经营发展分析

本文根据哲盟１９８５和１９９４年两次全盟森林资源二类调查，全盟有林地从３９．８万ｈｍ＾２增加到５７．２万ｈｍ＾２，年净增１．９２万ｈｍ＾２，森林覆被率由１０．８％提高到１６．７％，根据有林地变化动态进行分析，提出增加有林面积、提高森林覆被率的措施。     

两种模式的混合遗传算法的比较

为了提高遗传算法的精度,可在进化过程中引入局部搜索过程．一种方式是在每代进化过程中对每个个体都实施局部迭代搜索,另一种方式是只对每代的最优实施迭代搜索．实验表明,无论是解决函数优化问题还是解决组合优化问题（如TSP）,后一种局部搜索方式的性能都优于前一种方式．     

桥山林区矿山植被保护与恢复技术的探讨

通过对桥山林区矿山范围内生态环境破坏现状和相同生态区位废旧矿山植被恢复情况进行调查分析,提出了黄陵矿区矿山植被保护与恢复技术措施,为保护当地生态环境提供技术支撑。     

基于集水区法的森林生态系统影响径流研究进展

森林生态系统结构复杂, 具有减少地表径流、调节河川流量、减小土壤侵蚀等一系列保护环境的功能。森林植被变化对森林水文过程的影响会改变水量平衡方程的各个变量, 从而影响森林流域的水分分配和河川径流量, 进而对陆地生态系统水分循环起到重要的调节作用。从森林结构、森林类型、森林覆盖率和森林经营4个方面总结了国内外基于集水区法研究森林生态系统影响径流的结论, 即小流域的研究结果认为森林的减少将增加河川径流量, 而大流域的研究结果认为森林的减少将减少河川径流量。最后指出, 在研究单位和研究项目合作研究的基础上, 结合各相关学科的新兴技术和研究设备, 通过整合相关学科的研究成果, 阐明森林生态系统水土保持过程与机理, 是今后森林生态系统水文服务功能研究的发展方向。     

基于GIS的林区公路路线设计

在林区公路建设中,传统的路线勘察方法成本高,耗时长.通过分析最佳路线的基本原理,阐述了应用ArcGIS的空间分析模块进行最佳路线选择的方法和步骤,并以某林场林区公路路线设计为例说明基于GIS的最佳路线分析的具体应用.基于GIS林区公路路线设计新方法的可行性,在很大程度上缩短了勘查中的工作量.