林业在可持续发展中的地位和经济贡献

可持续发展包括林业的可持续发展基于生态,社会和经济效益的互相依存。以此为主导思想,文章概括了世界各地专家、学者、政府官员和产业界人士在第１１届世界林业大会第５分会上围绕着“林业对可持续发展的经济贡献”的主题所发表的关于林业的经济贡献与可持续发展的关系、     

论林业在可持续发展中的战略地位

科教兴国与可持续发展是我国的两大发展战略．林业在可持续发展中始终处于基础和主体地位．发展中国家可持续发展的前提是发展，林业对我国经济建设与发展作出了重要贡献，并成为我国山区综合开发与消除贫困的新的经济增长点．林业对缓解人口压力和提高人民素质具有重要的地位和作用，在发展农业、增产粮食中具有突出地应，对解决农村能源实现农村可持续发展具有重要地位。     

用科学发展观指导林业实践

在新的历史发展时期，用科学发展观指导林业理论与实践，把科学发展观渗透到林业管理和林业改革的各个环节，更加有效地发挥林业的职能作用，为地区经济、社会的全面协调可持续发展做出应有贡献，是我们各级领导干部和林业工作者必须思考的重大问题。     

大力推进林业产业化加快生态建设的步伐

实施林业产业化是加快林业改革，实现林产品商品化和林业现代化，促进生态建设，发展林业经济，摆脱林业困境，提高林业综合效益的必由之路。呼和浩特市经过多年的艰苦努力，林业建设得到了长足发展，为改善生态环境、保证社会经济的可持续发展做出了贡献。但是，由于产业...     

江西省社会林业开发的理论与实践

论述了江西省林业以邓小平理论及党的方针政策为指导,贯彻可持续发展的科教兴国战略,开展全民绿化,消灭宜林荒山,建立自然保护小区,发展林业专业户,启动高效林业等生态建设与经济建设的有效实践。证明了社会林业在兴林富省、繁荣发展山区、乡村经济、提高农户收入等方面的重要作用与巨大贡献。     

林业育苗现状分析及对应措施

以我国经济而言,林业建设在对经济发展做出贡献的同时,又提高了我国森林资源的占有率。发展林业,不仅是林业经济建设的必然要求,也是实现可持续发展和生态发展的必然选择。发展林业,离不开植树造林,植树造林又必然涉及到幼苗的培育工作。本文在阐述我国林业育苗现状的同时,从林业育苗技术的角度针对林业现状中的问题给出了措施建议。     

新世纪衢州市森林资源经营的思考

衢州市地处浙江西部,是浙江“母亲河”钱塘江的源头,保护和发展衢州市森林资源,不仅关系我市生态环境和林业经济的发展,而且对整个钱江流域乃至周边区域的生态环境和经济的可持续发展都将产生深远的影响。为此,要根据国家林业局局长周生贤提出的新时期林业建设五大转变的思想,切实抓好衢州市的保护和发展森林资源工作,促进林业的发展,为衢州市经济社会可持续发展作出应有的贡献。森林资源现状分析从上世纪70年代开始,衢州市共进行了五次5年间隔的森林资源连续清查。根据1998年第五全市森林资源连续清查结果,全市土地面积88.65万hm2,林业用地…     

丰宁县林业可持续发展的问题与对策

可持续发展,以人类的持久生存和福利需求的满足为目的。丰宁是一个山区县,经济落后,相对于人口的总量和增长趋势来说,自然资源承载能力有限,再加上自然环境复杂、基础脆弱、灾害频繁发生。这就决定了林业作为发展的重要手段之一,在丰宁社会经济发展中,肩负着物质产品贡献、环境服务贡献、市场供给贡献、要素结构优化贡献和协调人与森林生态系统之间关系的使命。因此,按照可持续发展理论的要求,分析丰宁林业发展中的问题,并提出相应对策是十分必要的。１　可持续发展的条件丰宁满族自治县是河北省林业大县。现有森林面积３３万ｈｍ…     

《中国国家自然保护区》学术专著开始编撰

为反映新中国成立50年来自然保护区建设成就,在维护生态环境、保护频危物种,实施经济和社会可持续发展中的作用和贡献。中国老教授协会林业分支委员会与安徽省科技出版社正在合作编辑出版《中国国家自然     

开拓进取 稳步前进

林业是国民经济发展的重要基础,是促进经济社会可持续发展的关键支撑。林业调查规划设计作为林业建设宏伟蓝图的绘制部门,必须紧跟国家经济发展战略的部署,进行业务拓展,才能生生不息,辉煌永存。作为林业调查规划设计部门,内蒙古自治区林业监测规划院（以下简称内蒙古规划院）深刻领会中央把林业地位提升到空前高度的重大战略意图,要为构筑祖国北疆重要生态安全屏障,建设生态文明,推动民生林业,促进整个经济社会可持续发展做出应有的贡献。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.