Testing the accuracy of resistance drilling to assess tree growth rate and the relationship to past climatic conditions

Assessing tree growth trends over time is a central but challenging aspect of urban forest management. The potential damage caused by invasive devices used in dendrochronological analysis is a common concern among urban foresters. Thus, the development of a less-invasive method for assessing tree growth rate faster that provides reliable results is clearly beneficial. In this study, resistance drilling (RD) profiles were compared with stem core assessments (Core) to estimate the growth rate of 78 trees of three species (Quercus robur, Ulmus procera, and Platanus x acerofolia). All studied trees were core-sampled in 2013 and then resistance drilled in 2015 at a stem height of 1–1.3 m in both north (N) and west axes (W). The dependency and accuracy of paired annual ring series (CORE measurements and Resi reading) were tested using ANOVA and regression analysis. In addition, point and event year tests were determined to confirm the accuracy of the RD to assess growth trends at both population and tree level. Growth series from both methods were cross-dated to test the reliability of RD to relate historical tree growth to past climatic conditions. ANOVA analysis confirmed that average ring width values and age of 70 out of 78 trees were statistically similar for both methods and similar for both sampled stem axes. Within each tree, regression analysis indicated significant correlation between cored ring datasets and paired resistance drilled ring datasets (R² = 0.78–0.95, p < 0.05) across species. RD reliably detected pointer years at population level for Q. robur only. For all species, RD could not adequately detect event years at tree level. Regardless of species and drill axes, RD was less accurate in measuring ring width below 1 mm. For all species, RD yielded lower intercorrelation indices and greater number of “A” flagged segments as compared to CORE. Overall, RD can successfully estimate mean annual ring values to a comparable standard as conventional CORE analysis. However, the RD device used in this study did not detect the inter-annual growth pattern to the same standard as stem CORE analysis, RD should not be used to replace dendrochronology in climate-tree growth studies.     

基于可视化分析的中国知识转移研究热点与展望

[目的/意义]知识经济时代,知识已成为重要社会资源,而有效的知识转移将促进知识的交流与共享,对提高组织知识应用与创新能力起到不可替代的作用。知识转移领域的研究已有丰富的成果,但对国内各视角知识转移的研究综述有待完善。[方法/过程]选用CiteSpace软件,采取文献计量方法,对CNKI数据库中核心期刊、CSSCI、CSCD来源的与知识转移研究相关的2854篇期刊文献进行可视化分析,整合样本文献的核心作者、学术机构、关键词数据,并绘制体现研究主题动态的关键词知识图谱。[结果/结论]通过对文献关键词的突现时间序列、共现与聚类图谱、时间线图谱进行分析,从研究对象、原理分析、过程路径和研究方法4个方面构建了知识转移的研究体系,并从企业、图书馆和创新视角对知识转移进行研究展望:企业的知识转移研究将集中在新兴企业方面;图书馆的知识转移研究将逐步增加中介效应;创新视角的知识转移可引入与知识、技术、信息传递相关的议题,实现跨学科的研究创新。     

苇状羊茅育种研究进展

苇状羊茅（Festuca arundinacea Schred）是我国广泛用于牧草生产、草坪绿化、生态修复等方面的草本植物。本文主要对苇状羊茅品种及育种进展进行总结。研究表明：苇状羊茅在我国存在大面积适宜区，适合大面积推广种植；近20年，一共有14个品种通过国家审定，其中5个自育品种均由常规育种技术得来；生物技术方面，已获得转Leafy-ipt，CRY8DB等基因的高抗病虫害株系，EST-SSR分子标记、指纹库也在建设中。未来苇状羊茅育种工作应该广泛收集野生资源；重视培育高消化率、抗腐霉病以及具有生态修复价值的新品种；育种进程结合高新技术，尝试引入“智慧育种”的概念；积极开发分子工具；引导使用国产优良种质，推动草产业发展。     

中国黑茶：起源与加工工艺

文章简述了四川黑茶、湖南黑茶、湖北老青砖、云南普洱以及广西六堡等黑茶的历史起源以及文化内涵，指出品质、工艺的独特性以及地域文化的差异造就了不同种类黑茶独特的发展历程；归纳总结了黑茶加工的基本工艺流程及工艺，并对比分析得出各地黑茶传统加工工艺的差异在于消费品质导向的不同以及精制过程中特色的紧压工序；结合品质调控以及规模化标准化生产的内在要求，提出对传统工艺的传承与创新以及机械化采制将是今后黑茶加工工艺改进的发展方向。     

我国农业领域创新方法应用探讨

基于创新方法在我国农业领域的应用概况,并结合目前已经开展的农业创新方法应用项目,总结出创新方法在我国农业领域的应用经验,并分析我国农业领域创新方法未来的发展应用趋势。     

环境监测现状和发展趋势探讨

指出了环境监测是认识环境、评价环境、掌握环境的重要手段,在环境科学发展中起着关键作用。对环境现状调查中发现的环境问题进行了分析,提出了相应的对策与建议,为环境保护工作提供参考。     

Identification of priority areas for controlling soil erosion

Conservation prioritization is an important consideration for planning of natural resources management, allowing decison makers to implement management strategies that are more sustainable in the long-term. However, only a current erosion status or a relative index cannot exactly identify priority area for conservation. The objective of this paper is to identify conservation priorities by a specific multicriteria evaluation method. Trends in erosion risk indicate regions of increasing erosion risk and are also chosen as one of the evaluation criteria to identify the priorities based on the instability of soil erosion in the Yongding river basin. In this paper, vegetation cover, land-use, and slope gradient are used to assess erosion risk and trends in erosion risk are obtained by comparing the results of erosion risk between 2000 and 2006. Using this information, the priority conservation areas are graded into six levels. The two highest priority levels cover the regions with severe erosion or a substantial recent increase in erosion risk (4722.56 km², or 11.82% of the study area), and are recommended as erosion control regions with appropriate conservation strategies. The middle two levels cover the regions with stable erosion status or slight change, needing only minor measures. The method presented is fast and straightforward, showing good potential for successful application in other areas.     

Declines in common, widespread native birds in a mature temperate forest

Common, widespread species are important for ecosystem structure and function. Although such species have declined in some parts of the world, for most ecosystems there is a lack of information about changes in the population status of common species. We studied the abundance of common, widespread forest birds in Nelson Lakes National Park, New Zealand using standardised 5-min bird counts, carried out over a 30-year time span. There was a significant change in the bird community structure during this period. Five native species (bellbird, rifleman, grey warbler, New Zealand tomtit and tui) declined in abundance during the 30 years. All of these declined in abundance at low but not high altitudes, and the decline was substantial for all but New Zealand tomtit and tui. Three other native species increased in abundance (silvereye, yellow-crowned parakeet and New Zealand robin). There was no change in the abundance of introduced blackbirds. We suggest that invasive alien species are the most likely cause of the ongoing declines in common native species. A peak in brushtail possum abundance and the arrival of a new species of Vespula wasp were two large changes in Nelson Lakes forests that occurred during this study. Both are likely to have added to the ongoing impacts of predation by introduced rats and stoats. We suggest that it is necessary to actively manage introduced species in order to maintain populations of widespread, common native bird species in New Zealand.     

全球大鸨的现状及种群发展趋势

2010年大鸨的全球种群数量估计为44100-57000只,其中57-70%分布于西班牙,俄罗斯的欧洲部分占15-25%,中国、蒙古及俄罗斯东南部共占4-10%,葡萄牙占3-4%,匈牙利占3%,土耳其占1-2%,其余零星分布于其他10个国家.在这次估算和调查结果中,大部分统计数据(占全球种群数量的67-75%)的可靠性很高,其余25-33%(分布于俄罗斯、蒙古国、中国、土耳其、乌克兰、伊朗、哈萨克斯坦等国家)或因调查不完善或因数据陈旧导致可靠性较低.虽然有报道称部分国家(如土耳其、伊朗和中国)的大鸨种群数量持续下降,但本次调查表明,在过去的10年里,全球种群数量并没有明显减少,与目前有关全球种群数量呈下降趋势的预测恰恰相反.这是由于近些年在大鸨主要分布区(如西班牙、葡萄牙)开展了全面、稳定的调查,使结果更准确;且在这些国家制定禁捕令后的几十年里,大鸨数量有明显恢复.仅在生活着全球大鸨总数的6-10%的地区,种群数量仍存在明显下降的现象,这主要是由于农业活动加剧以及栖息地退化、非法捕猎、触碰高压线等原因造成的.只有极少部分(占全球种群数量的3-4%)因管理和保护措施得当,种群数量有明显的(德国、奥地利)或显著的(匈牙利)增加.占全球总数的19-22%因当前或过去的调查不准确,现状和种群发展趋势不明确.因此,我们建议:1)继续保护该物种以及对全球现状的关注;2)为更准确地估算大鸨全球数量和趋势,应在种群资料相对缺乏的国家尽快展开全国性的调查.     

近年我国养鹿业发展动态

从鹿业的市场行情、鹿业生产技术及生产用品的开发状况、鹿产品的开发利用现状和鹿业的发展趋势 4个方面概述了近 3年来我国鹿业的变化动态 ,着重论述了鹿茸的行情变化 ,销路走势 ,鹿只销售价格的变化以及形成的原因等。