华北落叶松人工林大径材培育综述

我国大径材原料供需形势严峻,培育华北落叶松人工林大径材可以缓解用材紧张现状。笔者在借鉴他人对桉树、杉木大径材培育研究的基础上,从优质种源、立地条件和栽培技术3方面综述了华北落叶松人工林大径材培育技术,以期为华北落叶松人工林大径材培育提供理论参考。     

近自然经营理念在落叶松人工林经营中的应用

落叶松人工林是我国东北地区森林资源的重要组成部分,解决落叶松人工林生态环境问题、实现落叶松人工林的可持续发展,是东北林区森林经营的重要任务之一。文章通过阐述近自然经营理念、特征及优点,论述其在落叶松人工林经营中的应用,建立适合东北地区落叶松人工林近自然经营的两种模式,即落叶松-阔叶树混交林培育模式和落叶松-红松混交林培育模式,为落叶松人工林的可持续经营理论和实践提供参考。     

日本落叶松与天然萌芽阔叶树人工混交培育效果的分析

通过对日本落叶松与天然萌生阔叶树人工混交林的调查分析,结果表明:日本落叶松与天然萌芽阔叶树人工混交培育降低了培育成本,提高了生态效益,混交林培育28a后,林分生长稳定,生产力较高;混交林中的植物种类丰富,数量较多,各层次的物种多样性指数均好于人工营造的日本落叶松与白桦针阔混交林和日本落叶松纯林;日本落叶松与天然萌生阔叶树人工混交林,对恢复森林生态原始林貌有一定促进作用。     

落叶松培育远程咨询系统的研究与实现

本文研究了落叶松培育、专家系统中知识库的结构,并结合理论对落叶松远程咨询系统进行了详细的功能设计,确定运行环境和系统结构。通过使用一系列方法,对落叶松培育的相关知识进行获取,并加以整理和提炼重点,利用数据库技术进行知识库的组织。推理机部分采用正向控制策略,模拟专家解决问题的思路。最后,完成了落叶松培育远程咨询系统,并以林口地区作为实验对象进行验证。     

塞罕坝3种落叶松的生态鉴别

<正>塞罕坝以乡土树种华北落叶松为主要造林树种。60年代引进了落叶松(亦称兴安落叶松)和黄花落叶松(亦称长白落叶松),通过造林、培育和物候期观察证明,其生态     

落叶松—红松复层林培育技术及效益分析

根据多年在落叶松人工林培育方面的试验研究成果,系统地提出了落叶松-红松复层林培育技术,主要包括上层林木抚育、冠下栽植以及调控技术。上层保留林木的郁闭度应控制在0.5~0.6,冠下栽植红松后12年内适时伐除上层落叶松,为冠下幼树的生长创造条件。     

落叶松菌根苗的培育技术

文章详细阐述了落叶松菌根真菌的菌种生产、菌落培育和菌苗造林须遵循的技术要点,就落叶松菌根真菌的培育及在造林上的应用提出了自己的观点。     

塞罕坝机械林场培育混交林的研究

该文对塞罕坝机械林场不同林班落叶松纯林和落叶松与桦树混交林中落叶松的生长量进行了对比分析,结果表明混交林可促进林木生长,并阐述了培育混交林的其它优点。     

氮磷钾矿物质营养元素对西伯利亚落叶松(Larix sibirica Ledeb.)幼苗生长的影响

为了获得优貭高产的苗木,并缩短苗木在苗圃中培育的时间,必须实行一系列培育苗木的技术措施。最合理地供给苗木营养物质,是一项重要的育苗技术措施。苏联有一些人如等曾用营养栽培法研究木本植物对养分的需要。他们一致认为落叶松(西伯利亚落叶松,苏卡乔夫落叶松等)对肥料的反应良好;落叶松需要 P 肥量比 N、K 大得多。     

不同家系落叶松人工林生长的比较研究

本文以辽宁省清原县10个不同的无性系的落叶松为研究对象,采用样地调查数据以及年轮生长数据,采用方差分析和多重比较的方法,比较不同落叶松胸径、树高的生长特点,确定该地区最适宜种源,为落叶松的常规育种工作提供量化的指标,以指导落叶松培育实践工作。     

改革和完善森林采伐管理制度,确保生态建设长足发展——以呼和浩特市森林采伐为例

文章根据呼和浩特市森林采伐管理中存在的问题,分析问题存在的原因并提出相应的解决措施,以便适应新时期对森林经营提出的更高要求。同时,对群众反映最大、意见最多和表现最为明显的现行采伐制度的管理方面做了有益的探讨,确保森林采伐既达到保护森林资源的目的,又能够充分调动广大群众参与林业生态建设的积极性,以便早日实现林业生态建设跨越式发展。     

Current Research and Development on Deformation and Fixation of Bended Wood and Wood-based Composites

There are many advantages of bended wood,such as good-looking shape,simple process and low cost.The product,however,is easy to get recovery,which is urgent to be dealt with.This paper concludes the features of deformation and recovery of bended wood and wood-based composites and summarizes four treating methods to keep dimensional stability.Compared to bended solid wood,some elementary perspectives on the research of bended wood-based composites are presented.The purpose of this paper is to suggest:1)to investigate the optimum heating time and temperature that bended wood and wood-based composites need from the formation of deformation to the recovery and to the permanent fixation,according to its changes of dimensional stability such as curvature radius;2)to measure the composites comprised of wood and adhesives on the changes of stress relaxation,dynamic viscoelasticity and crystal1ization field;3)to quantitatively analyze changes of the major components in wood cell wall polymers as well as the composites under heat/steam treatment and untreated conditions.It will be helpful for subsequent research to clarify on the mechanisms of permanent fixation of bended wood and also contribute to that of wood-based composites.     

板栗优质高产途径及其技术措施的研究

增加结果母枝粗度、减少生理落果、改善内腔光照条件、适当控制树冠体积、提高栗棚内的栗果数与栗果重、缩短由小年到大年的时间,以及适时防治病虫害是板栗优质高产的有效途径。同时提出了实现各途径的主要技术措施。     

林木低磷胁迫适应机制研究进展

土壤有效磷缺乏在自然环境中是一种非常普遍的现象,近年来世界各国针对植物的觅磷和耐磷机制进行了大量研究,然而目前相关的综述性报道多限于农作物,对林木低磷胁迫适应性的综述性报道尚不多见。在长期进化过程中,林木为利用土壤中现有的含量极低的有效磷,形成了各种适应低磷胁迫的机制。文中从林木根系的形态学变化、根系分泌物对土壤难溶性磷的活化作用、林木对土壤低浓度有效磷的吸收利用以及应对低磷胁迫的遗传调控等方面综述了低磷环境中林木的适应机制,为揭示林木对缺磷环境的适应机理、发掘林木自身对土壤有效磷高效率的吸收利用能力、以及进一步筛选林木的磷高效品种和合理经营管理人工林提供参考。     

西北型日光温室内不同风速对甜瓜叶片光合、呼吸等生理指标的影响

试验以优选早蜜甜瓜为试材,研究了不同风速对甜瓜叶片光合、呼吸、蒸腾速率的影响规律。结果表明,从气孔导度来看：1．5m／s时对甜瓜新叶生长最有利,0．7m／s时对甜瓜老叶生长最有利;从胞间CCh浓度来看：0．7m／s时对甜瓜新叶生长最有利,0．7m/s时对甜瓜老叶生长最有利;从净光合速率来看：0．7m/s时对甜瓜新叶生长最有利。0．9m／s时对甜瓜老叶生长最有利;从蒸腾速率来看：0．5m／s时对甜瓜新叶生长最有利,0．7m／s时对甜瓜老叶生长最有利。鉴于0．7rids风速对实验中10项指标中的5项有利。因此：甜瓜温室栽培的风速应以0．7m／s为宜。     

培育森林资源要走内涵增长的新路子

本文提出了培育森林后备资源的指导思想要实现６个转变：（１）森林更新方式由营造成片人工纯林为主向“人天混”上转变，（２）森林培育方式由粗放经营向集约经营上转变；（３）森林培育重点由人工造林向抚育天然幼壮林上转变；（４）种苗工作由常规技术向生物遗传工程技术上转变；（５）经营机制由单一全民造林向多元化造林上转变；（６）营林机构单一职能部门向公司化转变。这些举措对森林经营和营林体制改革都具有现实意义。     

不同处理对草莓试管苗瓶外生根影响研究

为了简化培养程序,降低培养成本,以草莓继代芽苗为瓶外生根试验材料,采用三因素三水平正交试验研究不同栽培基质、激素、激素浓度对草莓继代芽苗瓶外生根诱导的影响研究以及采用不同生根处理方式,对成活率影响研究,建立草莓组培苗瓶外生根的技术优化体系。结果表明:A1B3C3组合(草炭:蛭石=1:1,激素NAA400mg/L速蘸处理)获得76.7%瓶外生根率,基质类型和激素浓度对组培苗瓶外生根的影响达到了显著水平,而激素种类对组培瓶苗外生根率的影响不显著。A3B3C3(草炭:蛭石:珍珠岩=3:1:1,激素NAA400mg/L速蘸处理)为最理想的组合;瓶外生根率低于瓶内生根率5.1%、根系质量优于瓶内,根活跃吸收面积提高1.34%、瓶外苗比瓶内苗缩短移栽时间30～40天左右,移栽成活率提高15%左右。     

Determination of embedding strength of wood for dowel-type fasteners

Embedding tests parallel and perpendicular to the grain were conducted to produce a database of embedding strength of wood for the design of dowel-type joints. Dowel diameters were 8,12,16, and 20mm. Embedding strength was evaluated by the 5% off-set method and a maximum load up to 5mm displacement according to EN383. The embedding strength parallel to the grain evaluated by the former method showed values close to those obtained with the latter method, but they showed a significant difference in tests conducted perpendicular to the grain. The embedding strength parallel to the grain was 0.9 times as large as the compressive strength parallel to the grain regardless of the evaluation method. The embedding strength perpendicular to the grain evaluated by the 5% off-set method was four times as large as the compressive strength perpendicular to the grain. When the embedding strength perpendicular to the grain was evaluated by a maximum load up to 5mm displacement according to EN383, the ratio of embedding strength perpendicular to the grain to the compressive strength perpendicular to the grain decreased as the dowel diameter increased.Part of this paper was presented at the annual meeting of the Architectural Institute of Japan 1999, Hiroshima, September 1999; the 50^th annual meeting of the Japan Wood Research Society, Kyoto, April 2000; and the World Conference on Timber Engineering 2000, Whistler, Canada, July–August, 2000     

The challenges of effective model scoping: A FLORES case study from the mafungautsi forest margins,Zimbabwe

This paper explores the challenge of defining the scope of a systems model, emphasising three aspects: boundary, granularity and conceptual scope. The significance of these is illustrated by reference to a model of land-use decisions made in villages bordering on the Mafungautsi forest in Zimbabwe. The purpose of this model was to help policy players (Forestry Commission staff, non-governmental organisations, researchers and local people) to understand the impact of policy interventions on local people’s livelihoods. Scoping decisions that were made in building the Mafungautsi model were deliberately liberal, to encompass the interests of all participants in the modelling process. These decisions now present a range of serious challenges: the difficulty of model calibration, the computational expense of running simulations, and the difficulty for new users to understand the model. Facilitators of modelling teams need to consider the serious implications of giving everyone what they want and including all participants’ ideas in a model. In the long run, it may be better to be tough and reject many suggestions at the outset. The former approach is unlikely to lead to a tractable model, while the latter may ultimately offer greater satisfaction for all. We are grateful to the UK’s Department for International Development (DFID) and the European Community for financial support of this project. Thanks also to all of the ACM team who have contributed ideas on the process and content of the modelling work and who make it fun to undertake collaborative research. Thanks also to the participants in the Zimbabwe FLAC workshops for their input into the specification of the Mafungautsi model. Finally thanks to Robert Muetzelfeldt, Jasper Taylor, Jonathan Massheder, Fergus Sinclair and Jerry Vanclay for helping us to ride on the FLORES bandwagon.     

我国的绿色GDP核算研究:未来的方向和策略

文中简要回顾了绿色GDP核算的研究历史, 分析了现有水平, 归纳了现存问题, 在参考国际动向后, 指出绿色GDP核算研究是一项庞大的系统工程。在此基础上, 文中进一步提出完成这一工程的核心任务是研建“一个框架, 四类标准”, 和为核算实务创建绿色会计、环境资产评估等支撑条件。中、近期内完成向绿色GDP核算制度的转轨是不现实的, 但可以而且应当鼓励部门和地方开展案例研究, 而后是组织交流、改进草案, 进而确定框架和标准。文中最后指出, 鉴于国情, 与只是为了研制一套绿色核算制度相比, 通过资源与环境估价唤醒国民的环境意识, 更为优先, 也更为现实。