我国经济要发展中的问题及思考

为了落实我国“九五”期间增产５００亿ｋｇ粮食和基本消灭贫困现象等两大农村工作任务，通过对我国经济林产品供需现状分析和各类产品需求预测，提出了今后经济林发展战略目标、布局和品种结构规划，为林业部门制定经济林宏观调控计划提供了决策依据。     

我国经济林产品的发展现状及开发利用对策

综合介绍了我国经济林产品的发展现状及开发利用对策。我国一些经济林产品，如油茶、油桐、漆树、白蜡、板粟、等栽培历史悠久，产量居世界之冠；一些经济林产品的质量在世界上享有盛名，如桐油、核桃仁；近年来在一些经济林产品的开发利用上取得了一定的进展；如采用加温融合与加压压榨法提取橄榄油比常规压榨法提高出油量１４．０７％。     

建国50年我国经济林建设取得的成果与经验

经济林是我国的重要林种之一。建国以来，我国经济林取得显著成效。从１９８０年以来，全国每年营造经济林７０万ｈｍ＾２以上，１９９４年高达２００万ｈｍ＾２。据不完全统计，１９９８年经济林产品总产量达５４００万ｔ，产值１０００亿元。经济林已成为山区农村经济发展的一项新型主导产业。该文总结了建国５０年来我国经济林建设取得的成果与经验，介绍了“九五”我国经济林建设规划目标及其实现目标的措施。     

经济林学科方向预测及其技术路线图

经济林学科是我国创立的林学分支学科。21世纪以来,我国在经济林树种的组学与分子生物学、优异种质发掘与良种选育、栽培生理与优质高效栽培技术、经济林产品加工利用等方面的研究都取得了显著成效,有效支撑了经济林产业的快速发展。预测了经济林学科的发展趋势,凝练了学科未来发展的重点领域与重点技术,制定了我国经济林学科的中短期和中长期发展目标,绘制了未来经济林学科发展的技术路线图,提出了未来我国经济林学科发展的7大研究任务,即经济林产量、品质、抗逆等重要性状的形成机制与调控,经济林优异种质挖掘、评价及高效育种,生态经济型品种筛选及良种工程化技术,特色经济林优质高效生产关键技术集成与示范,特色经济林机械化、轻简化和智能化高效栽培技术的建立与应用,经济林产品(原料)规模化采后处理与贮藏保鲜,特色经济林产品加工与高值化综合利用。     

浅谈建立并完善经济林标准化体系

介绍了我国经济林发展现状,阐述了当前在经济林建设以及现有经济林标准化体系中存在的问题。指出建立并完善经济林标准化体系应遵循先易后难、突出重点和区域性的原则,从经济林生产规程、产品质量、产品加工、产品包装和产品检测机构等方面着手。     

我国经济林产业发展问题的探讨

在调查研究的基础上,提出当前我国经济林产业发展的问题,并就有关问题进行了探讨和分析,旨在为我国经济林产业发展的宏观决策提供依据,以引导生产者控制过热产品,发展特色产品,挖掘潜力产品,更好地发挥经济林产品在林业产业建设和农村脱贫致富中的优势作用。     

全国各省（区、市）经济林产品产量规模与增速排行榜

经济林产品产量，按照国家林业局现行统计规定范围，包括水果、干果、林产饮料、林产调料、森林食品、木本药材、木本油料和林产工业原料8个部分。经济林产品对促进国民经济发展、繁荣市场以及满足人们生产、生活需要有着重要作用。目前，我国经济林产品的生产水平怎样，其产量有多少呢？     

经济林产品国内外市场需求预测（1996－2010年）

随着世界经济的持续发展和对外贸易的日益扩大，经济林产品已经成为世界各国发展经济和扩大对外出口的主要产品。通过对影响经济林产品市场需求的要素分析和对经济林产品市场供求状况的回顾，对来来１５年（１９９６－２０１０年）国内外经济林产品市场需求进行了预测，并对当前经济林发展存在的问题提出调整设想。     

我国经济林产业化的战略与对策

改革开放以来，我国经济林产业建设得到了快速发展，取得了令人瞩目的成绩。据统计，到２０００年底，全国经济林总面积已达２７３３万公顷，年总产量６８８０多万吨，总产值１３２０多亿元，分别比“八五”末增长了２４％、５４．７％和５８．８％；已初步形成了以干果、水果、木本油料、木本药材、工业原料、调料香料、饮料、森林食品等八种类型为主的十大经济林特色化区域布局，打造了一大批国内外知名经济林产品；全国原有的贫困山区县或乡通过大力发展经济林，带动了与经济林产品相关的贮藏、加工和运输业的大发展，６０％以上的农民实…     

我国现代经济林产业体系建设的成就

为了推动我国经济林产业体系建设的稳步发展,综述了建国60年来特别是改革开放以来我国现代经济林产业化体系建设取得的十大成就:现代经济林产业化体系的建设;创建产品加工经营企业;经济林栽培的区域化;创建生产基地,实施无公害生产;生产经营实施良种化;经济林栽培经营的标准化;创名牌,保护产品地理标志;原产地域产品保护;发展非公有制经济林;农民组建林业专业合作社。     

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.