滇中地区地带性植被优势种及云南松元素背景值的研究

本文研究滇中地区地带性植被(半湿润常绿阔叶林)优势种和云南松的元素背景值测定了植物叶、地被枯落叶和土壤内13种元素含量。并进行相关分析,结果表明:1常量元素含量的变化范围较小。具有相对稳定性。可反映地区植物元素背景值和地球化学特征:微量元素含量的变化较大。受成土母质和周围环境的影响较大。2叶内元素含量与土壤中元素含量有一定相关性。3在植物叶内,某些元素之间呈现一定的相关性。4常绿阔叶林优势种与云南松叶内元素含量的异质性显著。5营养元素与重金属元素在植物一枯落叶—土壤系统的物质循环过程中有不同的特点。     

海南万宁礼纪青梅林（续完）

海南万宁礼纪青梅林（续完）梁淑群，林英，杨小波，黄世满，符史新，谢国干（海南大学）礼纪青皮林自然保护区植物名录面类植物门ＰＴＥＲＩＤＯＰＨＹＴＡ１松叶蕨科Ｐｓｉｌｏｔａｃｅａｅ１）松叶蕨Ｐｓｉｌｏｔｕｍｎｕｄｕｍ（Ｌｉｎｎ，）Ｇｒｉｓｅｂ２水龙骨科Ｐ...     

江西亚热带常绿阔叶林的生活型

笔者以井冈山、云居山、莲花山、庐山、大岗山、新建、永丰等地亲自考察的第一手资料以及有关植被资料,对江西亚热带常绿阔叶林生活型进行研究。亚热带常绿阔叶林均以高位芽植物占优势,比例为60—90％,北、中、南亚热带常绿阔叶林的高位芽植物占的比例分别为60—70％、70—80％、80—90％。随着纬度的降低和生态系统顺向演替,伴随着群落中的高位芽植物比例增加,地上、地面、隐芽植物成分递减。     

太行山南端森林变迁史的初步研究

本文系统的研究了太行山南端2200年(公元前206年前-1985年)森林变迁、森林生态效益和旱、涝自然灾害频数后,划分为七个时期。秦(公元前206年)前,森林植被完好,森林覆盖率在80％以上,自然生态良性循环,基本上没有旱涝灾害。至东、西汉426年间,森林植被减少,森林覆盖率下降至70％时,已出现了一般性旱涝灾害,均为142年一遇。三国至唐,森林覆盖率下降至50％,出现了特大干旱和特大水灾。此后,随着森林植被的继续减少,自然生态循环向着恶化方向日趋发展。至民国时期,森林覆盖率下降至5％时,旱,涝灾害频数分别为2.1年和1.4年一遇,灾害频繁,交替发生,生态循环极度恶化。建国以来,太行山南端境内的森林总的是发展趋势。党的三中全会以后,采取重大措施,森林植被走向稳步发展的道路。     

商丘市防护林害虫防治策略的回顾与探讨

通过对商丘市建国以来防护林区的发展及害虫防治的回顾,探讨了防护林区害虫的防治办法,提出了防治害虫的策略和建议。     

现代城市林业的作用及发展思考

在阐述当前我国城市化的现状及城市化对城市人居环境的不良影响的基础上，分析城市林业的组成与作用，提出当前城市林业建设管理中存在的不足以及发展现代城市林业的基本思路。     

Loess in the Tian Shan and its implications for the development of the Gurbantunggut Desert and drying of northern Xinjiang

Eolian loess is widely distributed on the various geomorphic surfaces between 700–2400 m a.s.l. on the northern slope of the Tian Shan. It is formed in a synchronous manner with dust transported from the Gurbantunggut Desert in the Junggar Basin. The thickest section of loess was found in the Shawan and Shihezi regions. Paleomagnetic and climatic proxy analyses of over 71 m of a loess-paleosol sequence on the highest terrace of the Qingshui He (River) in the Shawan show that the paleomagnetic Bruhues/Matuyama (B/M) boundary lies at the bottom of paleosol S8, at a depth of 69.5 m, and the bottom of the sequence was estimated to be ∼0.8 Ma. This implies that the extremely dry climatic conditions in the Junggar Basin and the initial Gurbantunggut Desert were present at least by 0.8 Ma. High-resolution grain size series demonstrate that this area and desert expansion experienced two dramatic periods of desert expansions that occurred at ∼0.65 Ma and 0.5 Ma, respectively; and the subsequent continuous enhancement led to the environment presently observed. This tremendous environmental effect, caused by large-scale expansion of the desert and arid region of inner Asia, might be an important driving force for the global temperature drop that occurred in the mid-Pleistocene.     

Palaeolake and palaeoenvironment between 42 and 18 kaBP in tengger desert, NW China

Comprehensive field investigations and laboratory analyses show that palaeolakes, including fresh- mesohaline water Megalake Tengger and other semi-con- nected, isolated water bodies, during late Pleistocene covered an area of more than 20000 km², which is more than half of the Tengger Desert in NW China. Stratigraphic correlation and chronological evidence indicate that before ca. 42000 aBP the area was more arid. The palaeolakes started to develop around 40000 uncal. ¹⁴C aBP but until 37000 ¹⁴C aBP their scope was limited. High water levels established from 35000 ¹⁴C aBP lasted until 22000 ¹⁴CaBP. Lake levels regressed between 22000 and 20000 ¹⁴C aBP but transgressed from 20000 to 18600 ¹⁴C aBP. Subsequently, water level declined further and the Megalake Tengger finally desiccated at around 18000 ¹⁴C aBP. Megalake Tengger possessed a fresh-mesohaline water property, implying that the regional precipitation increased significantly. During the period of Megalake Tengger, the climate was warmer-humid than present. The annual rainfall was 250 to 350 mm more than that of today and the temperature was 1.5 to 3.0℃ higher.     

长白山阔叶红松林冠层空气动力学参数的计算

以大气边界层理论为基础，根据高大森林冠层区空气质量守恒原理，对长白山天然阔叶红松林冠层空气动力学参数进行了数值计算。结果表明，在不同天气背景下，零平面位移和粗糙度长度不是常数，但其季节性变化是主要的。在生长季节零平面位移约为19－20m，粗糙度长度约为1.2-1.3m，非生长季节零平面位移明显减小，只有14－15m，而粗糙度则明显增加，平均达2m以上。并讨论了这两个参数在相关研究领域中的应用方法。     

热带森林不同生长时期的小气候特征

利用西双版纳热带森林生长循环过程不同时期（林窗期、建群期、成熟期）干热季小气候观测资料，探讨了热带森林不同时期森林群落的小气候特征。结果表明，在干热季，不同森林群落的小气候与旷地存在显差异，森林具有显的降温增湿效应。由于不同生长时期森林的生物群落结构不同以及郁闭度和热力性质等的差异，导致不同森林群落的降温增湿作用不尽相同，各小气候要素随时间变化状况也存在差异，这将对不同生长时期森林群落的植物生长、发育等产生影响。