Wood Production Potentials of Fenno-Scandinavian Forests Under Nature-Orientated Management     

《Scandinavian Journal of Forest Research》2012,27(4):445-454

In Finland, Norway and Sweden forest management is presently changing towards a more nature-orientated management. In this study the European Forest Information SCENario (EFISCEN) model was applied to determine how this change might affect the potential for wood production in the three countries. Three different management regimes, traditional, traditional with nature conservation (''conservation''), and longer rotations with nature conservation (''conservation +''), were combined with two alternative felling levels. The results show that conserving 6.1-8.8% of the older forests in the southern regions had no limiting effects on production levels, as foreseen by the European Timber Trend Studies V by the UN-ECE for Finland and Sweden. Under the conservation + scenario, maximum sustainable felling levels decreased to 84, 79 and 72% of the present levels in Finland, Norway and Sweden, respectively. Increasing the rotation length put more pressure on the older age classes and thus did not increase the average age of the forest. If the consumption of wood increases as quickly as indicated by other studies, it will be hard to fulfil that demand and at the same time conserve considerable areas of forest in the southern regions of the countries.  相似文献   

农业科研院所因公出国（境）管理研究     

陈丽珍  郑玉  罗海燕  姚庆群 《安徽农业科学》2014,(15):4886-4888

以中国热带农业科学院热带作物品种资源研究所（以下简称：热科院品资所）为例子,分析热科院品资所因公出国（境）现状、存在问题并提出了解决对策。  相似文献   

农牧业实行家庭承包经营的比较分析     

许小宁 《青海草业》2012,21(1):39-41

本文通过对农牧业（种植业和养殖业）中实行家庭承包经营责任制的比较分析,旨在阐明在畜牧业中实行草畜分包经营的合理性。联系实际提出了几点措施。  相似文献   

基于决策支持的棉库管理系统设计与实现     

郑娜  李倩茹  马文惠 《安徽农业科学》2012,(5):3002-3003,3097

根据棉库管理的业务需要,规划设计了基于决策支持的棉库管理系统平台总体框架。阐述了系统的平台架构及组成,分析了系统软件组成结构、系统开发工具及技术的选择、人机对话系统设计等系统的实现。  相似文献   

我国烟草业改革之路   总被引：5，自引：0，他引：5  

韩灵梅 《河南科技大学学报(农学版)》2003,23(4):70-72

针对目前我国烟草行业发展中存在的经营管理体制不完善、行业整体技术水平较低、“两烟“市场基本饱和、入世后国际竞争加剧及社会舆论环境对烟草行业的发展压力加大等问题,提出了深化烟草行业体制改革,大力推进企业组织结构调整,建立和完善专卖制度下适应市场经济要求的烟草市场体系等改革发展思路。  相似文献   

Passive transfer of colostral immunoglobulins in calves     

Weaver DM  Tyler JW  VanMetre DC  Hostetler DE  Barrington GM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2000,14(6):569-577

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum gamma-glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.  相似文献   

Promoting and preserving biodiversity in the urban forest   总被引：1，自引：0，他引：1  

Alexis A. Alvey   《Urban Forestry & Urban Greening》2006,5(4):195-201

Efforts at mitigating global biodiversity loss have often focused on preserving large, intact natural habitats. However, preserving biodiversity should also be an important goal in the urban environment, especially in highly urbanized areas where little natural habitat remains. Increasingly, research at the city/county scale as well as at the landscape scale reveals that urban areas can contain relatively high levels of biodiversity. Important percentages of species found in the surrounding natural habitat, including endangered species, have been found in the urban forest.

This contribution concisely highlights some examples of urban biodiversity research from various areas of the world. Key issues involved in understanding the patterns and processes that affect urban biodiversity, such as the urban–rural gradient and biotic homogenization, are addressed. The potential for urban areas to harbor considerable amounts of biodiversity needs to be recognized by city planners and urban foresters so that management practices that preserve and promote that diversity can be pursued. Management options should focus on increasing biodiversity in all aspects of the urban forest, from street trees to urban parks and woodlots.  相似文献   

日粮和管理对东北虎血液指标及免疫功能的影响     

王兴金  赵云华  陈黎龙  黄志宏  李婉萍  李少基  谢高基 《野生动物》2007,28(1):21-24

从营养和管理方式均不同的两组东北虎群中各选5只体型适中的成年雄性东北虎作为研究对象，其中笼养组以纯肉为日粮，散养组以混合饲料为日粮。麻醉后采集静脉血，测定血液中各项生理生化指标，外周血淋巴细胞增殖性反应，以及血清中白细胞介素-2（IL-2）、白细胞介素-6（IL-6）和肿瘤坏死因子（TNF）的含量。结果：散养组外周血淋巴细胞增殖性反应显著高于笼养组（P〈0．05）；血清尿素、肌酐、淀粉酶、谷丙转氦酶、谷草转氦酶等指标在两组间差异显著（P〈0．05）：全血红细胞计数、白细胞计数、血红蛋白含量、血清蛋白、甘油三酯、总胆固醇等指标组间差异不显著（P〉0．05）。结果显示：营养和管理方式对东北虎某些血液指标产生影响，混合日粮和散养方式更有利于维持东北虎的正常免疫机能和健康。  相似文献   

Significance of leaf infection by Botrytis cinerea in stem rotting of tomatoes grown in non-heated greenhouses     

D. Shtienberg  Y. Elad  Ariela Niv  Y. Nitzani  B. Kirshner 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(8):753-763

The most serious symptom of Botrytis cinerea in tomatoes grown in greenhouses is stem rotting. Lesions on the stem may result from direct infection or from progression of the rot along infected leaves, until infection approaches the stem. In a set of experiments conducted in commercial greenhouses, an experimental greenhouse and growth chambers, the significance of the two types of stem infections was studied. In non-heated greenhouses most of the stem lesions originated from progression of the pathogen along infected petioles. The rate at which B. cinerea had progressed on infected petioles was 0.3–0.5 cm/day, an average of ca. 6 weeks was needed for a leaf infection to approach the stem. Application of Trichoderma harzianum T39 extended this time by 1–2 weeks and application of chemical fungicides by 3 weeks. Influence of the environment on the progression of B. cinerea along infected petioles was then determined. Within range of 5–30 °C, the higher the temperature, the more rapid was the rate of disease progression. The fungus progressed more rapidly on tomato petioles incubated at high vapour pressure deficit (VPD) rather than at low VPD. The source-sink relationship of the plant governed the rate of B. cinerea progression along the petioles as well: it was more rapid when the source was restricted (by shading) and slower when the sink was restricted (by removal of flowers and small fruits). The possibility that sanitation of infected leaflets would reduce the incidence of stem rotting was examined in two experiments. In plots not treated with a fungicide, the sanitation treatment substantially decreased the incidence of stem lesions and this treatment was as effective as weekly application of chemical fungicides.  相似文献   

有关人造板建设项目投资控制的几点看法     

沈兰君 《林产工业》1998,(5)

强化人造板建设项目的投资控制,要求加强可行性研究的管理,纠正可研工作中存在的问题,提高可行性研究质量;同时,加强技术与经济的结合,以提高投资效益为中心,并根据“合理造价”的原则,通过调研和综合分析、比较,准确框定投资估算,为投资决策与强化投资控制提供科学依据。  相似文献