大熊猫栖息地主食竹类种群结构和动态变化

１９８４～１９９０年在卧龙自然保护区大熊猫生态观察站，海拔２３００～３４００ｍ地带，对主食竹种拐棍竹（Ｆａｒｇｅｓｉａ ｒｏｂｕｓｔａ）和冷箭竹（Ｂａｓｈａｎｉａ ｆａｎｇｉａｎａ）种群的空间结构和数量动态进行了探索性的研究。初步了解到它们的种群数量动态变化的消长规律，可作为保护和发展大熊猫的食物基地提供科学依据。     

Using Landsat images to detect oak decline in the Mark Twain National Forest, Ozark Highlands

Following the severe drought in 1999–2000 there was a widespread outbreak of oak decline in the Ozark Highlands. Over 400,000 ha of dead and dying oak trees were observed by the USDA Forest Service in this region. Although oak forests that are dead can be easily interpreted from air photos or classified from satellite images, it is difficult to detect dying trees that are still green but will die back or recover in the following years. In this study, we applied a normalized difference water index (NDWI) to map the continuous forest dynamics related to oak decline. The Landsat TM image in 1992 and the ETM+ image in 2000 were processed to calculate the differential NDWI which revealed moisture variation primarily caused by the drought and the associated red oak borers. A simple thresholding method was used to map oak dying back, recovery and non-change areas in the study area. The died-back areas were extracted from the modified land use/land cover maps created by the Missouri Resource Assessment Partnership (MoRAP). The forest dynamics map was compared with the online FIA database in which tree species at randomly selected sites were recorded in 1989 and 2003. The overall accuracy of forest dynamics mapping with remote sensing imagery was 75.95%. The user's accuracy of dying/recovery area mapping was also high although the producer's accuracy is questionable because of the limitation in ground data collection. The continuous dying/recovery map in this study could provide valuable information on the prediction of oak decline and evaluation of damage when another period of environmental stresses occurs.     

人工林地力衰退现状及防治对策

通过对落叶松和杉木等人工林连栽作业引起地力衰退的研究表明，生物循环失调，栽培技术不当是引起人工林连栽地力衰退的主要原因。人工林地力衰退主要表现为土壤剖面逆向发育，土壤理化性质变差，有机质和养分状况恶化，人工林生产力下降等，指出调整林分结构、保护林下植被，营造混交林，科学经营是缓解人工林地力下降的重要措施。     

攀枝花市凤凰木衰退病因的研究

对攀枝花市凤凰木衰退病发生原因的调查研究表明该病的发生是多方面因素共同作用的结果,归纳为诱发因子(predisposing factors),如空气污染严重、年降雨量分布不均匀、土壤粘重板结、土壤瘠薄等恶劣环境因素.激化因子(Inciting factors),受干旱严重重复发生的胁迫、霜冻及凤凰木夜蛾(Pericyma cruegeri)、尺蠖(Buzura suppresaria)等食叶害虫的年年严重危害.促进因子(Contributing factors)受凤凰木根腐病、端齿材小蠹(Xyleborus     

森林衰退病研究现状及展望

文章对我国森衰退病的研究现状和发展概况进行了综述，并介绍了国外有关臭氧、酸沉降及森林衰退病与立地相关性等研究的重要进展。对于Manion的森林衰退病概念中的若干问题如非生物和生物因素的顺序、衰退病最终结果是导致树木死亡、森林衰退病的起因等进行了讨论。最后对我国森林衰退病研究提出了几点建议。     

Changes of soil properties in the colonies of the common cormorant,Phalacrocorax carbo

The edaphic environment in the colonies of the common cormorant (Phalacrocorax carbo) was investigated to detect the effects of cormorant's defecation on plants through the soil. Some properties of the soil down to 50 cm depth in the cormorant's colonies in Chikubu Island and Isaki Cape (Lake Biwa, Shiga Pref., Japan), were compared against those of the soil on the outside of the colonies in 1992. On the inside of the colonies, soil acidification over the whole soil layer, which has been considered to accelerate the accumulation of toxic ions such as Al³⁺, and increase in moisture content at the depth of 5 and 15 cm, which would inhibit the growth of roots, were recognized. Thus, plants in the colonies of the common cormorant were likely to suffer various negative effects through changes in soil environments mainly due to continual supply of faeces onto the ground.     

Der Einfluß gasförmiger Luftschadstoffe auf die EpicuticularWachse von Quercus robur

Influence of gaseous pollutants on the epicuticular wax of Quercus robur . The effects of SO₂, NO, and ozone on the epicuticular wax of Q. robur were studied by scanning electron microscopy and by measuring the contact angle of water droplets on the leaf surfaces. The treatments did not induce any significant differences in the wax micromorphology.     

森林资源消长与营林对策

对丽水市１９７５年以来森林资源动态与营林成效进行分析结果看出，经过２０年的人工造林、封山育林，使森林资源持续增长，有林地面积增加，荒山、疏林基本绿化，总体蓄积量回升，林种、龄组结构趋于合理，经济果木林有较大幅度增长，但也存在林分总体素质差、单位面积产量低、人工造林保存率高而效益不理想，封山育林成果巩固难度增大等问题，提出营林工作要转向提高林分内部质量的战略，调整产业结构，大办绿色产业，巩固和扩大绿化成果，提高林业综合效益。     

异丙草胺在玉米和土壤中的残留及消解动态

采用气相色谱-微池电子俘获检测器(GC-μECD)测定了900 g/L异丙草胺乳油在土壤、玉米植株和玉米籽粒中的消解动态和最终残留。土壤、玉米植株和籽粒样品用石油醚-丙酮(1∶1,体积比)提取,经液液萃取,弗罗里硅土柱净化,GC-μECD检测,外标法定量。结果表明:异丙草胺在各供试样品中的添加水平为0.011～1.1 mg/kg时,回收率在78.8%～96.4%之间,相对标准偏差(RSD)为0.54%～10.5%;在土壤、玉米植株和籽粒中的定量限(LOQ)均为0.011 mg/kg。异丙草胺在土壤和玉米植株中的半衰期,2009年分别为4.7～5.3 d和4.1～4.5 d,2010年分别为5.4～5.5 d和4.9～5.4 d。按推荐高剂量(有效成分)2 400 g/hm2及其1.5倍剂量(3 600 g/hm2)施药,于玉米苗后茎叶初期施药1次,在玉米乳熟期和成熟期时,玉米籽粒中异丙草胺的最终残留量均低于定量限。玉米收获时(距施药45 d),土壤和玉米中的异丙草胺残留量均低于参考的MRL值(0.1 mg/kg),说明按规定在玉米田使用900 g/L的异丙草胺乳油是安全的。     

壬基酚聚氧乙烯醚及其降解产物壬基酚在香蕉和土壤中的消解动态及风险评估

为评价农药助剂壬基酚聚氧乙烯醚(NPnEO)在香蕉上使用的安全性,于2009-2010年在海南采用田间试验和超高效液相色谱-荧光分析方法研究了NPnEO及其降解产物壬基酚(NP)在香蕉及土壤中的消解动态和最终残留。结果表明:NPnEO在香蕉及土壤中的消解规律符合一级动力学模型,其半衰期分别为8.8~12 d和6.9~8.5 d,而其降解产物NP在香蕉和土壤中的半衰期分别为16~18 d和24~26 d。在香蕉收获期,NPnEO及NP在香蕉中的残留量均低于0.01 mg/kg。通过计算得出每人每天从香蕉中所摄入的NP仅为0.09 μg,风险商值(RQ)为0.003,处于安全水平。