Biodiversity policies in commercial boreal forests: Optimal design of subsidy and tax combinations     

Erkki Koskela  Markku Ollikainen  Timo Pukkala 《Forest Policy and Economics》2007,9(8):982-995

This paper examines the first-best instruments for biodiversity maintenance in commercial boreal forests when landowners behave either in Faustmannian or Hartmanian way. Using an extended Hartman model, we show that biodiversity conservation requires both prolonged rotation age and leaving retention trees. While the former promotes some old growth species, the latter create new structural elements of decaying and dead wood, which can sustain a variety of saprolyxic species. A fully synchronized combination of retention tree subsidy and tax instrument is needed both to lengthen the privately optimal rotation period and to provide an incentive to leave retention trees. Using Finnish data we illustrate empirically the sizes of instruments. When combined with a harvest tax, the retention tree subsidy is 1000 and 750 € in the Faustmann and in the Hartman model, respectively. When used with a timber subsidy or a site value tax, the retention tree subsidy is 1700 €/ha in both models. The harvest tax rate varies over the range 40–65% in the Faustmann model and 20–40% in the Hartman model, while timber subsidy is between 0.5–1.0% and site value tax is about 1.75%.  相似文献   

日本龟蜡蚧在枣树上的发生与危害   总被引：3，自引：0，他引：3  

李新岗  黄君伟 《陕西林业科技》1997,(3):51-54

１９９６年８月￣１９９７年６月，在陕西大荔县八鱼乡西营村和蒲支县平路庙乡直杜村调查了日本龟蜡蚧在枣树上的分布与危害。结果表明，单叶幼虫数随枣树受害程度的增加而增加，单果重随枣树爱害程度的增加而减少，越冬雌虫的危害造成每股的抽吊数减少，吊长显著变短，每吊的刺树数减少，幼虫和雌成虫在树冠上的分布是阳面（南面）大于阴面（北面），其中树冠中部虫量分布的最多。  相似文献   

我国人造板工业发展趋势预测与原料创新研究   总被引：6，自引：0，他引：6  

陈琳  孙琦  周定国 《林业科技》2005,30(5):45-47

围绕我国木材资源短缺和人造板工业高速发展的现状，阐述我国人造板原材料演变的历程。农作物秸秆作为绿色原料，在河南、山东、江苏、黑龙江等省份储量丰富。本文从工艺、成本、环保等角度，分析其作为人造板原料所具有的优势，并讨论了21世纪中国秸秆人造板工业的发展前景。  相似文献   

Organic Matter Added to Bareroot Nursery Beds Influences Soil Properties and Morphology of Fraxinus pennsylvanica and Quercus rubra Seedlings     

Anthony S. Davis  Douglass F. Jacobs  Kevyn E. Wightman  Zonda K. D. Birge 《New Forests》2006,31(2):293-303

Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings (Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha⁻¹ (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m³ ha⁻¹. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl). Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak, but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the proper balance can improve seedling morphological quality and positively influence soil chemical properties.  相似文献   

城市大环境绿地的类型、数量与分布(英文)   总被引：4，自引：0，他引：4  

王晓俊 《林业研究》2001,12(1):67-70

城市大环境绿地在维持城市物质与生态环境方面的作用随着城市扩展而日趋重要。良好 的大环境绿地规划可以使城市形成较为健全的绿色空间系统。本文对城市大环境绿地的七种 类型进行了初步划分，着重讨论了大环境绿地规划中的数量问题和规划布局的基本原则。  相似文献   

家具产业的发展与绿色思维   总被引：10，自引：1，他引：10  

胡景初 《林产工业》2001,28(2):3-5

以全球性可持续发展的战略思想为背景，就与家具产业发展相关的绿色产品设计与开发、生态工艺的应用，以及绿色消费观等进行了探讨，提出了可持续发展的产品开发方向，工艺技术路线，以及家具消费文化等新观念。  相似文献   

Chemical Composition of Green Tea (<Emphasis Type="Italic">Camellia sinensis</Emphasis>) Infusions Commercialized in Portugal     

Reto M  Figueira ME  Filipe HM  Almeida CM 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(4):139-144

To evaluate the potential benefits and risks associated with tea consumption it is important to identify the constituents of this beverage. Levels of some minerals, caffeine and catechins in green tea samples commercialized in Portugal were evaluated. Potassium is the metal present in larger amount (92–151 mg/l). The content of sodium, calcium, fluoride, aluminium, manganese and iron were 35–69, 1.9–3.5, 0.80–2.0, 1.0–2.2, 0.52–1.9, 0.020–0.128 mg/l, respectively. Chromium and selenium were not detected. The resulting data showed considerable variability in catechins content. The levels of epigallocatechin gallate (EGCG) ranged from 117 to 442 mg/l, epicatechin 3-gallate (EGC) from 203 to 471 mg/l, epigallocatechin (ECG) from 16.9 to 150 mg/l, epicatechin (EC) from 25 to 81 mg/l and catechin (C) from 9.03 to 115 mg/l. Caffeine contents in the green tea infusions studied were between 141–338 mg/l. Green tea infusions provide significant amounts of catechins and could be an important source of some minerals.  相似文献   

欧盟共同农业政策:绿色生态转型、改革趋向与发展启示     

张鹏  梅杰 《世界农业》2022,(2)

农业是引发温室气体增多、生物多样性下降以及水体污染等生态安全事件的主要产业之一。在种种生态安全事件的挑战下,农业应该朝着绿色生态的方向进行转型已经成为多数国家的共识。欧盟的共同农业政策是世界上较早提倡农业绿色发展的农业政策之一。从1992年开始的麦克萨里改革到已经达成的《2023—2027年共同农业政策》临时协议,欧盟共同农业政策绿色生态转型体现出政策支持更加明确、以农民利益保护为重点、自愿性与强制性措施相结合、以数字技术为支撑以及多政策配套实施等改革趋向。在强调绿色发展与转型的新时代,欧盟共同农业政策的改革历程及发展趋向可以为中国农业政策改革提供一定的经验及启示,通过优化顶层设计、健全补贴机制、坚持弹性原则、提高科技能力、增加政策协同等措施来推进农业的绿色生态转型。  相似文献   

RNAi转基因大豆品系‘B5C9123-5’的RPA可视化检测技术     

张晨  雷展  李凯  李飞武  商颖  许文涛 《中国农业大学学报》2022,27(1):50-57

为开发RNAi转基因作物的田间可视化鉴定方法,以DNA嵌合染料SYBR Green I为材料,采用设置重组酶聚合酶扩增(Recombinase Polymerase Amplification,RPA)特异性引物的手段,建立了一种快速、低成本、可视化的RPA用于转基因大豆‘B5C9123-5’的检测。结果表明,在靶标不存在时,RPA体系中游离的SYBR Green I染料使溶液呈现较弱的黄色荧光。在靶标存在的情况下,RPA扩增产生的双链DNA与SYBR Green I结合导致溶液从黄色转变为绿色并使荧光迅速增强。通过对RPA扩增时间和温度进行优化,阳性结果可在20 min内用肉眼鉴别,检测限为1.00 ng/μL。通过设置不同RPA引物,该方法可用于现场快速检测多种RNAi转基因作物。  相似文献   

江苏省张家港市水稻常见绿色防控措施原理及优点分析     

李可懿 《现代农业科技》2021,6(6)

水稻病虫害的发生严重影响水稻产量。化学农药和化肥的大量使用对农业生态造成不良影响,也易导致病虫害抗药性的产生。笔者整理总结了近几年在江苏省张家港市的六种水稻绿色防控措施,分别分析了其防控技术原理及优点,以期为指导当地绿色防控工作开展提供理论参考。  相似文献