Status of floor vegetation under some monoculture and mixculture plantations in North India

A study conducted to assess the floor vegetation shows the presence of 17 species underPopulus deltoides in comparison to 28, 29 and 35 underAlbizia lebbeck, Dalbergia sissoo and mix-culture plantations, respectively. Further, the biomass and density of floor vegetation is considerably reduced underP. deltoides compared to other plantations. In addition, the indices for species richness, evenness, dominance and diversity are also reduced underP. deltoides showing some inhibitory mechanism being operative under these plantations. Based on available literature, allelopathy is speculated to be responsible for this reduction.     

轿子山自然保护区植被类型及其保护价值评价

依据《云南植被》编目系统，将轿子山自然保护区的植被划分为7个植被型，9个植被亚型，16个群系，20个群落，并对各植被类型的保护价值进行了数量化评价，在此基础上对保护价值较高的急尖长苞冷杉林、野八角一乳状石栎林、杜鹃矮林、杜鹃灌丛和元江栲林、高山柏灌丛等6个主要植被类型进行了评价。     

The effect of multi-nutrient fertilization on understory vegetation nutrient concentrations in inland Northwest conifer stands

This study looked at the effects that multi-nutrient fertilization had on understory vegetation nutrient concentrations at four conifer forested locations in the inland Northwest. Multi-nutrient fertilization of conifer stands cannot only enhance the overstory species in the inland Northwest but also the understory vegetation. Determination of nutrient concentration response to fertilization treatments can provide managers the ability to better manipulate their forests for grazing and wildlife habitat. We grouped the understory vegetation into three general life forms: forbs, grasses and grass-likes, and shrubs. Multi-nutrient fertilization had little effect on nitrogen concentration across all life forms. Potassium and sulfur generally increased in concentration. Micronutrients as a whole showed less variability in response to multi-nutrient fertilization. Boron, copper, molybdenum, and zinc generally showed increases in concentrations across all life forms. We were able to conduct analyses on a selected number of understory vegetation species. Individual species showed variability in nutrient concentration response to multi-nutrient fertilization. Wildlife habitat and grazing quality were both increased and decreased following multi-nutrient fertilization. Increases in nutrient concentrations will provide more nutritious vegetation to these animals and vice versa for decreases in concentrations.     

Apiculture and management of associated vegetation by the maya of Tixcacaltuyub,Yucatán,México

We present the results of field work and a series of interviews with Mayan beekeepers, in order to answer the following questions: (i) Which factors are relevant when establishing an apiary? (ii) How do Mayans choose the melliferous flora? (iii) How do Mayans manage the vegetation surrounding their apiaries? and (iv) What is their knowledge of flowering phenology and honey production cycle? Apiary establishment depends on: no apiaries established at a minimum distance of 3 km; water availability (i.e., “Haltunes”); direct access to roads; combination of old and young vegetation (particularly abundance of Gymnopodium floribundum). Melliferous flora is classified according to quality and quantitity of the honey produced; 34 species are considered important at different times of the year. Finest honey and arger quantities are obtained from G. floribundum, followed by Viguiera dentata; the worst honey is from Lysiloma latisiliquum. Management of vegetation is minimum, mainly cutting plants that could impede growing of important melliferous, or protecting ( = not cutting) the latter; nevertheless, some of the most important melliferous are dominant in the vegetation. Their knowledge of flowering phenology and production cycle are quite complex. We discuss the problems the beekeepers are facing in regards to forest clearing, commercialization of produces, etc.     

乌兰布和沙漠植被及其保护

乌兰布和沙漠降雨稀少,生态环境脆弱,有种子植物49科169属312种,以蒙古种、戈壁—蒙古种、戈壁种以及古地中海区系的荒漠成分占主导地位;自然植被为亚洲中部荒漠区与草原区的分界线,主要有梭梭、柠条、白刺和油蒿、沙冬青＋白刺＋油蒿、白刺＋红砂、白刺＋霸王＋油蒿、籽蒿＋沙竹、芦苇、白刺＋芨芨草等9类群丛。由于不合理的利用,草场植被逐年退化,正朝着极度荒漠化演变。对植被状况和平缓沙丘及半固定、半流动沙地等不同立地条件的草地,应因地制宜,造（林）封（育）飞（播）结合,开展综合治理,恢复植被,遏制沙漠化加重的趋势。     

乌海市平沟煤矸石山小地形土壤养分分析

文章以乌海市平沟煤矸石山上平台和边坡两种不同小地形上的土壤为研究对象,通过野外调查取样和室内分析化验,研究煤矸石山两种小地形对土壤养分的恢复情况。结果表明,土壤有机质、全N、碱解N含量在两种不同小地形上表现为边坡>平台,土壤P素、K素含量表现为平台>边坡,总体而言,边坡上土壤养分恢复效果比平台好。平台和边坡上土壤养分含量在不同土层深度中均表现为:0~20 cm层>20~40 cm层。通过参考土壤养分分级与丰缺度标准,目前土壤养分丰缺度主要呈现出缺或极缺状态。     

江西大岗山植被类型及其自然度与经营集约度的划分和评价*

１。采用样地法和点四分法在江西大岗山年珠、上村林场进行植被调查。主要植被类型有：栲楠常绿林、针阔混交林、竹阔混交林、杉木人工林、毛竹林、灌木林和山顶草地。该地区主要经营大面积杉木人工林和毛竹林，原地带性植被只剩下林相残破、零星分布的常绿阔叶林。２．提出自然度（植被与顶极群落的距离，分Ｖ级）与经营集约度（人工经营程度，共５等）对两林场进行了划分与双重评价。占人工林总面积３２．２６％的人工林经营良好，     

北京九龙山林地对降雨的调蓄功能*

对北京九龙山油松林、侧柏林、阴坡灌木林、阳坡灌木林的林冠层、枯落物层及土壤层对降雨的调蓄功能进行了研究，结果表明：四种不同林地的林冠截持率为２２％～３２％，大暴雨下的截持率为７％～１０％；枯落物层的有效调蓄为０．４６～２．４２ｍｍ；５０ｃｍ土层的快速、慢速和变化调蓄量分别为３５～４８ｍｍ；５４～４８ｍｍ，２８～５２ｍｍ；四种林地调蓄功能的顺序从大到小为油松林、阴坡灌木林、阳坡灌木林、侧柏林。     

封山育林是恢复和重建晋西黄土高原森林植被的重要途径

论述了晋西黄土高原封山育林的必要性、理论依据及可行性。分析了不同时期弃耕地和封禁小流域的植物演替和植被恢复规律。在黄土弃耕地上植物群落演替规律为：弃耕后,15a-20a为草本植物群落阶段;21a-25a可形成灌木群落;26a-30a能达到较成熟、稳定的灌丛群落;30年后,开始形成乔木林。黄土残塬沟壑区封禁小流域植被恢复情况为：经过12a,木本植物的种类达到了41种,分属于16科34属,其种源来源于周围残存的次生林。总结了封山育林的效果。     

辽西北地区植被分布组成与土地沙化关系的调查

在辽西北部地区土地沙化调查中,进行的植被调查结果表明,草本植被平均盖度为71.9%。由于草地面积减少与连年干旱的影响,湿生植物、中生植物分布缩小,而旱生植物分布扩大。出现频度最高的植物共20种,其中1年生田间杂草和沙生植物的总出现次数与数量高于多年生禾草和其他多年生植物,为其1.8倍和2.7倍。因此,该区植被退化与土地沙化发展比较强烈。这20种植物中过度放牧和极度放牧沙化植物的出现次数和数量高于适度放牧(包括不放牧)和重度放牧,可知过度放牧和极度放牧,是植被退化与土地沙化的主要因素。蒺藜草的分布频度达25.0%,多度达23.7%,已经成为当地草原的主要害草。