高黎贡山地区生态环境变迁状况与重建对策

20世纪中叶以前,高黎贡山森林植被茂密,生态良好.如今,大面积的原始森林被砍伐,滑坡、泥石流自然灾害不时发生,生态环境恶化.通过对高黎贡山地区的生态环境恶化的原因进行分析,提出了5个方面的生态环境建设对策:(1)恢复植被;(2)开发替代能源以降低薪材消耗;(3)调整土地利用结构以发展社区经济;(4)发展生态旅游;(5)借助保护区的优势,争取国内外支持援助.     

武威盆地沙漠化成因及整治途径

通过对武威盆地沙漠化成因及整治途径探讨表明：１．破坏植被和水源是造成土地沙漠化的潜在原因；２．过量开采地下水，造成水位急剧下降，是造成盆地生态环境恶化和土地沙漠化的根本原因，３．人口过速增长和牲畜头数成倍增加是沙漠化发展的内在原因；４．沙漠扩张，沙线东进南移是导致盆地沙漠化的直接原因。整治途径是：１．保护森林，开源节流，合理用水，２．加速盆地防护林体系建设；３．加强植被建设，保护好沙地现有植被。     

龙陵小黑山大雪山自然保护区的植被类型

1994．12－1995．1对龙陵县拟建中的小黑山、大雪山自然保护区进行了一次综合考察，其中的植被考察以线路调查为，样地调查为辅，该保护区的主要植被类型有（1）灌丛：多变石栎、杜鹃灌丛、地檀香灌丛；（2）常绿阔叶林：多变石栎、马缨花苔藓矮林，多变石栎林，木果石栎林，截头石栎、尖齿木荷林；（3）竹林：空心箭竹林；（4）落叶阔叶林：旱冬瓜林；（5）暖性针叶林；华山松林，秃杉林，云南松林，杉木林。     

若尔盖县沙漠化,潜在沙漠化土地继续扩大的原因及防治对策

若尔盖县沙漠化、潜在沙漠化土地继续扩大的原因及防治对策冯凉（四川省营林调查队）由于自然因素影响，人为活动破坏了植被和地表结构，生态环境日益恶化，导致若尔盖县沙漠化、潜在沙漠化土地继续扩大。为给子孙后代造福，草地资源应持续利用．有效地防沙治沙已成燃眉之...     

河谷生态环境质量新源排第一

伊犁州环保局统计分析结果表明：2005年，伊犁河谷生态环境质量排在第—位的是新源县；综合评价值接近良。此次生态环境质量综合评价以县（市）为单元，选用生物丰度指数、植被覆盖度指数、水网密度指数、土地退化指数和污染负荷指数作为评价指标，将伊犁河谷生态环境质量综合评价值分为优、良、一般、较差和差5个等级。     

简论我国可持续林业实施中存在的问题

可持续发展已成为全球广泛认同的林业发展方向，在简要回顾了我国林业可持续发展研究状况后，提出了在过程中存在的主要问题；（１）现在森林资源的不可持续性；（２）林业从业人员素质低下，经营方式粗放；（３）资金投入严重不足；（４）生态环境恶化，环境污染不为民加剧；（５）林业科技进步缓慢，缺乏在区域层次上林业可持续发展理论和实践的研究等。这些问题严重影响着林业可持续发展战略的具体实施。     

实施围封禁牧工程 构筑北部绿色屏障

党的十七大报告将“建设生态文明”作为我国在2020年实现全面建成小康社会奋斗目标的新要求之一。地处祖国北部边陲的达尔罕茂明安联合旗（以下简称为达茂旗），为遏制生态环境恶化，有效保护和恢复生态，提高林草植被覆盖率，在认真分析旗情的基础匕，以科学发展为统领，以构筑包头市北部绿色屏障为目标，及时做出“实施围封禁牧工程”战略。     

《湖南靖州县林业发展规划》编制完成

《湖南省靖州县林业发展规划（2003-2012）》近日已由湖南省林业调查规划设计院编制完成。《规划》预算未来10年靖州林业发展总投资达28931．6万元。其中国家投资占12、6％；省、市投资占1．1％；地方自筹占13、2％；银行贷款占35．8％；招商引资占37．2％。据测算，全县林业总产值到规划期末（2012年）可达到74305万元（按2002年不变价格计算），比规划期初（2002年）的4．6亿元净增2．8亿元，林业产值每年递增5，5％。《规划》的全面实施，将为发展全县林业，改善生态环境，建设靖州小康社会并最终实现经济的可持续发展奠定坚实的基础。     

关于恢复和发展星云湖泾流区森林植被的建议

通过对星云湖泾流区森林资源的调查,星云湖泾流区的水土流失较严重,环境日益恶化,直接威胁着星云湖泾流区的生态环境,为此,对星云湖泾流区森林植被及荒山荒地（难造林地）的特点进行了分析,并提出恢复和发展星云湖泾流区森林植被的建议。     

以森林植被重建引领黄河中游地区生态保护与高质量发展——以山西省为例

以习近平生态文明思想为指针,通过回顾反思黄河中游地区因森林植被减少而导致的区域生态环境恶化、经济社会发展滞后等后果,提出了"以森林植被重建引领黄河中游生态保护与高质量发展"的总体思路。并以黄河中游的山西省为例,归纳总结了在黄河中游地区开展森林植被重建、修复自然生态,需要重点做好的5个方面的工作。     

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.