Spasmolytic activity of several extracts obtained from some Mexican medicinal plants

A total of ten extracts from different parts of eight medicinal plants that are used in the treatment of gastrointestinal disorders, were evaluated to determine their spasmolytic action on in vitro isolated rat ileum. All extracts were less potent than papaverine, which was used as a positive control.     

Deforestation and degradation of natural resources in Ethiopia: Forest management implications from a case study in the Belete-Gera Forest

The major causes of deforestation and degradation of natural resources in the Belete-Gera Forest of Ethiopia are coffee production activities and encroachment into forestland to expand farmland and pasture. Population growth, and the government’s land-reform and re-settlement programs have caused local residents to lose harmony with the land. Forest management in this area hasn’t yet been fully developed. The objectives of this study are to identify the extent of deforestation and natural resource degradation, in preparation for a sound management plan. Encroachment of farmland and pasture into natural forest during the past four years has been identified through interviews and aerial photo interpretation. The encroachment rate is 1.45% per year. Encroachment occurred mostly on areas with gentle slopes adjacent to populated villages and along roads and footpaths. The extent and impact of coffee production activities were examined through agency documents, forest survey data and vegetation survey. It is estimated that up to 49% of the accessible natural forest is under the influence of coffee production activities, among which collecting of naturally grown coffee beans has the least and the coffee plantations has the most impact on the natural forest. Coffee plantations in natural forest have reduced the forest density and species diversity. Age structure of the trees is limited to mature and old classes only, which eventually endangers their function as shade for coffee plantations. This project was funded by the Japan International Cooperation Agency.     

Comparison of Forest Biomass Across a Human-Induced Disturbance Gradient in Nepal's Schima-CastanopsisForests

Abstract

This paper presents estimations of aboveground tree biomass (combined for boles and branches) in Nepal's Schima-Castanopsisdominated warm-temperate forests. The biomass estimations are presented for five forest stands purposively sampled in a larger study to represent different harvesting intensities. Two categories of biomass estimates are provided: (1) for living trees that are standing, and (2) for cut trees that have been removed. Biomass of standing trees were estimated by using diameter at breast height (dbh) and total height measurements as predictor variables in appropriate regression models. Biomass of cut trees were estimated in two steps: measurements of stump diameters and heights were used first to predict dbh and total heights of cut trees; these values were then regressed to obtain biomass estimates for the missing trees. Data were gathered from 2,361 live trees and 2,962 stumps in 170 sample plots across the five forest stands. Estimates of mean standing-alive biomass ranged from a minimum of 16 ton/ha in the severely disturbed forest to a maximum of 479 ton/ha in a relatively undisturbed (reference) forest. Estimates of mean cut biomass ranged from a minimum of 24 ton/ha in a second reference forest to a maximum of 183 ton/ha in the severely disturbed forest. The biomass estimates in the relatively-undisturbed, reference forests are well above the 95% upper confidence interval of the global mean. Similar findings of high productivity have been reported for temperate forests of the Central Himalaya in India and Eastern Himalaya in Sik-kim. The findings of this study in the Nepalese Central Himalaya support the conclusion that productivity potential is high in the temperate Himalayan forests. The study's findings and methodology should be useful for preliminary development of guidelines in the region to regulate forest biomass growth, yield, and harvest.     

浙江省良性林地流转与生态公益林建设互动机制研究

对非良性林地流转的界定及危害性进行了介绍,论述了良性林地流转对于生态公益林建设的意义,并分析了浙江省良性林地流转与生态公益林建设互动促进机制的因素,提出了构建浙江省良性林地流转与生态公益林建设互动促进机制的思路和具体内容。     

森林认证对白河林业局的影响分析

介绍了白河林业局森林认证的背景,根据实地调研获得的数据资料和在官方网站上收集的资料分析了森林认证对该林业局经济、社会和环境的影响。结果表明:白河林业局开展森林认证在经济上可行,使当地社会受益,对当地环境负责,促进了当地森林的可持续经营。     

不同强度间伐对长白山天然林林下植物多样性的影响

对吉林森工集团松江河林业局辖区内的阔叶红松林、杂木林和杨桦林采取30%～40%（T1）、20%（T2）株数强度的均匀间伐处理,以不间伐处理为对照（CK）,对间伐2 a后林下植物木本、草本植物进行调查,采用Simpson、Shannon-Wiener多样性指数和Pielou均匀度指数进行植物多样性分析,探讨不同强度间伐对3个林型林下植物多样性的影响。研究结果表明：T1间伐后3个林型的物种丰富度均有增加（杂木林木本植物例外）,T2间伐后杨桦林木本植物丰富度降低,草本植物丰富度增加。两种间伐处理均增加阔叶红松林木本植物多样性,T1处理尤为明显。T1处理增加杂木林和杨桦林木本植物多样性,而T2间伐处理有较弱的降低作用。两种间伐处理均降低阔叶红松林和杂木林草本植物多样性,与强度无明显关系。随着间伐强度的增加杨桦林草本植物多样性增大。在长白山天然林中,较大间伐强度T1（30%～40%）能够有效提高植物多样性。     

岷江上游亚高山典型森林植被群落数量特征研究

本文应用Shannon-Wiener多样性指数，Simpson生态优势度指标以及群落均匀度指标，定量研究岷江上游亚高山主要森林群落的组成结构特征。以原始林的数量特征为参照，比较分析了岷江上游亚高山植被自然恢复与人工恢复的群落数量特征。结果表明，岷江上游亚高山主要森林群落的物种多样性指数为0.55～4.62，多数在1-3之间，多样性指数值偏低。生态优势度为0.06-0.92，多数在0.40-0.80之间。群落均匀度为0.27～1.39之间。原始林的群落组成及结构特征取决于人为干扰程度。在森林植被恢复过程中，人工营造的混交林的群落结构优于自然恢复的次生林的群落结构，因而具有较好的生态效应，而人工营造的纯林的群落结构则比自然恢复的次生林差。人工林的林木生长速度大于天然更新的林木。     

林网化与水网化——中国城市森林建设理念

建设森林城市要求有足够的森林面积和通畅的水循环系统。本文以上海为例提出在人多地少与水系统不很通畅的中国发展城市林业必须走林网化和水网化的道路。为探索具有中国特色的城市森林发展新理念。作者从理念的内涵、依据、过渡和国内外比较研究等几方面作了阐述。       

The Lintula Larch Forest

The Lintula Larch Forest, also called the Raivola Larch Forest, is one of the most magnificent cultivated forests in northern Europe. It has had a major impact on the cultivation of larch throughout the world, and it became part of the Unesco's World Heritage list in 1991. This article summarizes for the first time to an international audience the establishment, administration and management, stand development and research carried out in Lintula Park. It is based on Russian and Finnish papers and earlier unpublished results. The forest is located 63 km north-west of St Petersburg in the Karelian Isthmus. It was established by order of Peter the Great to supply the Russian fleet with timber for shipbuilding. Ferdinand Gabriel Fockel, a German forest expert, established the oldest stands in 1738–1750 with seed from the Province of Arkhangelsk. Since then the area of the forest has expanded and now the total area of larch stands is 55.9 ha; 23.5 ha of the “old stands” established in 1738–1851 still remain. The Lintula larch stands were famous for their high yield, but part of the reputation was based on small sample plots that were not representative of the stands. However, the high volumes of different tree stands are impressive. For example, in a 255-year-old stand with 339 trees ha^?1 the volume of growing stock was 1284 m³ ha^?1. In small sample plots much higher volumes are found. The average annual growth of the oldest larch stands has never exceeded 6.2–7.2 m³ ha^?1. The volume increment was, however, long-lasting, and annual growth started to decrease only after 148–166 years. Some plots had an increase in yield even at the age of 257 years. The yield of the larches clearly surpassed that of Norway spruce and Scots pine in nearby stands. The Lintula Larch Forest has provided valuable experience on the cultivation of larch. The root system of larch is relatively weak, and it is therefore susceptible to wind damage and rot fungi. An important conclusion drawn from the development of the Lintula Larch Forest is that the cultivation of larch is worthwhile only when grown as pure stands using intensive growing techniques.     

林业分权管理政策研究--谈绥宁县森林资源村集体管理

改革森林资源管理体制一直是林业部门讨论不休的问题 ;文中探讨了湖南省绥宁县森林集体经营管理模式产生的背景以及不同时期其内涵的变化 ;通过分析 2 0a来集体管理的成效及成功因素 ,总结了它的启示意义及采用这一管理模式所需的社会和体制条件     

减少毁林和森林退化引起的排放:一个综述视角的分析

减少因毁林和森林退化引起的温室气体排放(REDD)对控制和减缓全球气候变暖具有重要作用。UNFCCC第11次缔约国会议将REDD议题列入气候谈判议程, 希望REDD成为2012年后承诺期减缓气候变化的重要措施之一。文中在对国际社会关于REDD的谈判进展和指导原则等进行概述的基础上, 探讨了当前国际社会关注的REDD的焦点问题, 分析了这些焦点问题的现状及其可能的发展趋势, 并据此提出讨论和建议。     

从历史文献看竹林防护作用

本文通过历史文献探讨古代中国人对竹林防护作用的认识,注重发挥竹林防护城市和居民住宅安全、调节气候、涵养水源、保持水土、减弱噪音、净化空气、防风等保护生活环境的作用。     

天然苦竹林的改造

改造天然苦竹林能充分保护和利用天然林资源。改造天然苦竹林主要包括选择立地等条件好的天然林,通过炼山或不炼山,对竹林进行清杂、整理、深翻去“三头”、施肥、抚育等技术措施。     

Forest Growth-and-Yield Modelling

Abstract

Examples of effective growth-and-yield model implementation and use are documented throughout the forestry world. However, in the perspective of sustainable forestry, comparing the development of management requirements with growth-and-yield research backgrounds, some doubts arise concerning basic research hypotheses. The conflict between the necessary simplification implied in models development and the essential complex nature of forests plays a key role in the issue. Furthermore, present modelling concepts stem from a traditional framework relying at the fundamental perception level on the enforcement of external regulations on the forest, having some predetermined optimal structure as a goal. If tomorrow's strategic planning places in the forefront of the framework Oldeman's paradox “objectives are best achieved by first forgetting them in favour of forest survival and complexity maintenance,” we will really face quite a sharp concept change. Yet, it is important to clearly focus the role of models as potential adjuncts to the professional judgement and wisdom of foresters given their rational scientific character as learning, communication and screening tools. What is attainable is not the high precision of quantitative predictions, at least as far as complex biological systems such as forests are concerned. Compact representations (e.g., minimal models and “modeles simples”) with few state variables and a biologically-driven content may provide reasonable indications on future states over a wide range of conditions, contributing to operational forest management guidelines within an adaptive framework.     

商品林采伐限额管理制度国别经验

对森林采伐进行必要限制是世界各国的通常做法。文中对美国、巴西、德国、俄罗斯、芬兰和新西兰6个林业典型国家的商品林采伐限额管理审批制度进行分析, 总结其可供借鉴的国别经验及启示, 针对我国现行商品林采伐制度存在的突出问题提出改进和完善的对策建议。     

The Rotation Problem and Tropical Deforestation in Forest Economic Textbooks: A Comparative Review

In the past three decades, new trends have been influencing the field of forest economics. For example, the optimal rotation literature has focused increasingly on risk and uncertainty analysis and there has been a steady increase in the number of economic studies regarding tropical deforestation. In this article, it is investigated whether the emergence of these topics is reflected in relevant textbooks of the discipline. Moreover, some structural textbook attributes are analyzed and compared, namely the use of illustrative elements and pedagogical aids. Our results show that one can clearly recognize a steady development in the texts.     

社区是有效保护天然林的主体

自然保护区管理的实践证明，仅靠政府的投入而忽略社区的角色和作用是难以实现自然资源的有效管理的。天然林保护工程的实施面临着来自当地社区的比自然保护区管理更大的压力。社区林业的实践表明以社区为基础的森林资源管理可能是天然林有效保护的途径之一，社区将是天然林有效保护的主体。     

Experimental determination and modeling of equilibrium moisture content from the sapwood of Mexican pine (<Emphasis Type="Italic">Pinus pseudostrobus</Emphasis> Lindl.)

A desorption isotherm is a very important basis in the understanding of drying process. In this study, the desorption isotherms from the sapwood of Mexican pine (Pinus pseudostrobus Lindl.) were determined by the gravimetric method (discontinuous control of sample weight) at 30℃ and 50℃. The salt method was used in the range of water activities from 0.11 to 0.89. The results show that the desorption ability of Mexican pine sapwood increased with temperature at a given relative humidity. The experimental data was further simulated with the models, i.e., BET, GAB, Oswin and Henderson models. The GAB, Oswin and Henderson models allow the representation of the entire desorption isotherms. The BET model showed a better fit for water activity lower than 0.35, with a mean relative deviation of 0.0286 at 30℃ and 0.0167 at 50℃. Simultaneously, the BET model gave a better representation of moisture content in the monolayer saturation region. Overall, the GAB model ensured the best simulation of the entire isotherm, while the Henderson model displayed the worst simulation.     

德兴市国家重点生态公益林中幼林抚育及低效林改造探讨

国家重点生态公益林是以保护和改善人类环境、保护生态平衡、保存物种资源、科学实验、森林旅游、国土保安等需要为主要经营目标的森林,直接关系到国家安全,生态安全和广大人民群众的根本利益。     

日本森林体验的发展及启示

森林多功能利用是目前国内外研究与开发利用的热点.日本以其丰富的森林资源为平台, 以康体、教育体验为纽带, 开发利用森林体验, 取得了丰硕的成果, 为其他国家及地区提供了经验与启示.文中介绍了日本森林体验开发利用现状, 详细分析了其森林体验指导者培训与考核机制、森林体验基地建设、森林体验推广营销等策略, 提出了我国开展森林体验的相关建议, 可为我国的森林多功能利用提供借鉴.