眉县两次气象站迁址对温度资料序列的影响分析

选取经历两次迁址的眉县气象站和周边2个未迁过站址的参照站1974～2017年年平均气温、年平均最高气温、年平均最低气温资料,对比分析了迁址对眉县站温度序列的影响。结果表明:两次迁址和城市热岛效应的共同影响使得眉县站温度变化趋势与参照站产生较大差异。眉县站44年来年平均气温和最高气温升幅比参照站明显,最低气温升幅小于参照站;近44年两站气温差值随时间波动位相基本一致,且与眉县站两次迁址时间刚好对应;年平均气温差值序列有3个不连续点,年平均最高气温差值序列有4个不连续点,年平均最低气温差值序列有5个不连续点,每个时段平均值差异显著;热岛效应和迁址使得眉县站温度年代变化趋势不一致;造成气温差异的主要原因是测站周围环境的变化和下垫面性质的变化。     

长白山西南坡野生鸟类资源分析

长白山西南坡位于吉林省东南部,128°17′51″~125°16′04″E,40°51′40″~43°00′49″N,总面积33 240 km2。该区属温带大陆性气候,四季分明,但冬季漫长、寒冷。年平均气温2·1~6·5℃,最高气温35~37℃,最低气温为零下35~40℃。年降雨量为686·3~945·1 mm。区内大小河流220     

刘公岛植被现状及价值分析

刘公岛位于威海市境内,北纬37°52′~54′,东经122°26′~30′,最高点旗顶山海拔159.5m,总面积3.15km2。刘公岛南面坡度平缓,北面地势陡峭,成土母岩主要为石灰岩、片麻岩等岩类。土壤有棕壤、沙壤等土类。刘公岛属暖温带季风型大陆性气候区,历年平均气温12℃,8月份气温最高,月平均气温24.7℃,最低气温在1月份,月平均-1.9℃,历史极端最高气温35.5℃,极端最低气温-14.7℃,阳坡比阴坡早解冻半个月。年平均无霜期220天,始霜期10月底,终霜期4月中旬。夏季多南风,冬季多北风、西北风,历年最大风速40m/s。年平均降水量为750.2mm,多集中于7、8、9三…     

惠山国家森林公园游憩林小气候与人体舒适度变化规律

【目的】研究无锡市惠山国家森林公园典型游憩林内小气候及人体舒适度的时间变化规律,以期为惠山乃至江南地区游憩型城市森林的合理经营和生态效益评价提供基础科学数据,也为当地市民选择合适的时间和衣着开展森林游憩活动提供参考。【方法】在惠山国家森林公园最高峰附近,选择20世纪80、90年代营造、位于山顶南坡的香樟林、湿地松林和山顶北坡的栓皮栎林3种典型人工游憩林为对象,以位于山脊的水泥道路为对照,于春、夏、秋、冬季晴好无风天气条件下,在5:00—19:00同步测定3个游憩林及对照点的气温、空气相对湿度和风速,在此基础上计算舒适度指数和衣着厚度指数,量化分析各游憩林及对照点的小气候、人体舒适度的季节变化、日内变化规律,比较不同游憩林的人体舒适度差异,并提出四季游览惠山的衣着建议。【结果】各林分温度的季节变化表现为夏季>春季>秋季>冬季,空气相对湿度表现为夏、秋季大于春、冬季,风速表现为香樟林和湿地松林在夏季最大,栓皮栎林和道路在秋季最大;相同季节不同林分之间的舒适度指数差异不显著,各林分在春季的人体舒适度最高;4个季节白天观测时段内,各林分气温日变化均为单峰型,且峰值出现在11:00—15:00,谷值出现在 5:00 —7:00,空气相对湿度的日变化规律则与气温相反;风速的日变化趋势波动较大,峰值出现在5:00—9:00,谷值出现在13:00—15:00;在春、秋、冬季,各林分人体舒适度在11:00—15:00最高,而夏季这个时间段则最低;3个游憩林在夏季能显著提高人体舒适度,但冬季与对照的差异不大;各林分气候达到“舒适”等级的时间为春季最长(11:00—17:00),秋季次之(11:00—15:00),夏季仅早上气候舒适(5:00—7:00),冬季气候均为“极不舒适”;各林分的着衣厚度指数在夏季均为1,冬季均为7,春季香樟林为5,湿地松林和栓皮栎林为4,道路为3,秋季道路和栓皮栎林为4,香樟林和湿地松林为5。【结论】 3个人工林林分在春季均发挥降温增湿效应,湿地松林在4个季节都具有降风作用;各林分在夏季调节小气候效应更明显,春季的人体舒适度最高,春、秋、冬季的11:00—15:00为白天气候的最舒适时段。     

河北雄安新区近50a气温变化特征

为科学掌握雄安新区气候特征,为雄安新区建设提供基础数据保障,基于雄安新区区域内3个国家气象观测站的多年气象观测资料,采用线性回归分析、Mann-Kendall突变检验和小波分析等统计分析方法,系统分析了雄安新区近50 a气温的时间序列变化、突变现象、周期变化特征。结果表明:(1)雄安新区年平均气温呈显著波动升高趋势,气候倾向率为0.265℃/10 a,略高于全国平均气温变化速率;不同季节平均气温升温对年平均气温的贡献为春季冬季夏季秋季。(2)平均最高、最低气温均呈波动升高趋势,气候倾向率分别为0.238℃/10 a、0.422℃/10 a,平均最低气温升温趋势显著;平均最高气温不同季节的升温幅度为春季夏季冬季秋季,平均最低气温的升温幅度为春季冬季夏季秋季。(3)年、冬季、春季和夏季平均气温增暖趋势均存在突变现象,年平均最高气温自90年代开始呈现持续增暖趋势,突变点为1990年。年平均最低气温及各季节的平均最高气温、平均最低气温的增温趋势不存在突变现象。(4)年平均气温存在8 a、13 a、19 a周期变化,年平均最高气温存在8 a、11 a、19 a周期震荡,年平均最低气温存在13 a、19～20 a周期震荡。雄安新区气温研究结果对全面认识该区域气候特征及变化趋势系具有一定的现实意义。     

毛竹林内夏季气温变化的特征比较

定位研究位于浙江省富阳市的不同结构毛竹林,2003 年夏季林内气温的日变动状况。结果表明:毛竹林内以日最低气温的变异幅度最大,日最高气温次之,日均气温最小;毛竹纯林内日均最低气温21.20℃,低于竹阔混交林1.32℃,日均最高气温为29.67℃,低于竹阔混交林1.03℃。毛竹林内最低气温主要出现在凌晨 4:00￣6:00,毛竹纯林调节林内最低气温的效应值与栎林相似约-0.3℃,竹阔混交林效应值约1.25℃。方差分析显示毛竹纯林、竹阔混交林、茶园3类林分间的日均气温差异极显著,日最低气温差异显著。     

普洱地区冷暖冬划分标准和对热带农业的影响

研究认为,云南普洱市热区大部冬季平均气温大于10℃,按《中华人民共和国国家标准暖冬等级》的标准划分冷、暖冬,与实际气候对农业的影响及公众对气候的感觉有不一致,经引入年极端最低气温、冬季最低旬平均气温和冬季平均气温三个气象因子,就能更合理地划分普洱热区冷暖冬,更好地满足热带农业的需求和服务社会公众的需要;研究还表明,普洱市近50年来冬季气温不断增高,但每隔10年左右仍会有全市范围或局地的冷冬事件,热带种植业须要增强对冬季低温灾害的防御意识。     

峨眉山圈养大熊猫夏季昼夜活动节律

了解圈养大熊猫活动节律有助于改善大熊猫的饲养管理。本研究采用连续时间记录法于2014年7月~9月对峨眉山熊猫馆的3只大熊猫的昼夜活动节律进行了调查。结果表明,平平和香琳的活动曲线相似,1天之内有3个高峰期和1个次高峰,芦琳则有4个活动高峰期和两个次高峰。在9:00~10:00和16:00~17:00这两个时间段3只大熊猫同时处于活动的高峰期,活动率在66±22%~89±37%之间。建议将投喂大熊猫的时间安排在大熊猫的高峰活动期间,以助于提高大熊猫的进食效率,减少食物的浪费。     

喀什地区多措并举 狠抓林业抗冻减灾工作

喀什地区受西伯利亚南下冷空气影响，2008年1月16日-27日，普遍出现降雪，积雪深度达10-17cm，此次降雪天气范围之广、雪量之大、持续时间之长为近三十年罕见。降雪结束后，最低气温从1月27日-2月1日已连续6天低-20℃，其中2月1日麦盖提县-27℃、伽师县-25．5℃、岳普湖县-25．2℃、莎车县-24℃、巴楚县-25．2℃，     

燕龙板栗光合作用及其相关因素的日变化

为了改进板栗栽培技术,提高其光合效率,以2年生板栗品种"燕龙"为试材,研究了板栗的光合作用及其相关因素的日变化。结果表明:板栗净光合速率的日变化呈双峰曲线型,有明显的午休现象,分别在10:00和15:00出现高峰,10:00的峰值较高,13:00~14:00出现"午休"现象;去雄后,板栗叶片光合速率下降;板栗叶片气孔导度日变化与光合速率的变化趋势一致,而蒸腾速率日变化呈单峰曲线型,峰值出现在13:00;胞间CO2体积分数在午休期间较高。午间随着光照强度的增加,气温和叶温升高,蒸腾速率增加,气孔导度和光合速率下降。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.