城市生活污泥在林业上的应用综述

目前,人们对工业化迅速发展和城市人口急剧增长所产生的污水厂污泥的处理予以高度重视,土地利用被认为是最有发展潜力的处理方式.文章试图从城市生活污泥对森林植物、森林微生物与森林土壤的作用,综述近几年来城市生活污泥在森林与园林绿地、矿区植被恢复与高速公路绿化带等方面的研究与应用.     

在高等林业院校开设“城市林业”课程的思考

（一）城市林业概念及其形成的基础城市林业以城市森林为研究对象，主要内容是研究在城市开放空间种植树种的选择，城市森林规划设计、营造、培育与管理，城市森林的利用和效益的评价与发挥以及城市森林与人口、城市建设、城市环境的相互关系。纵观历史，人类和为人类更好生存而建设起来的城市是在森林的哺育下成长起来的。在这一过程中，努力从森林怀抱中挣脱出来的人类，以为开辟了新的生活境地，再也无需回到森林的怀抱，于是人类把森林当成了取之不尽、用之不竭的财富，大肆毁林，造成了人类历史上一次次不堪回首的惨剧：受到幼发拉底河…     

城市森林：城市生态建设新坐标

城市森林是由多种植物构成的有机复合体，由于它的发展历史不长，如今还在不断探索和实践之中。目前，专家们从不同角度对城市森林和城市林业有不同的理解，尽管还没有一个公认的城市森林概念，但已达成一定共识：城市森林是以木本植物为主的植被体系；这种植被生长环境为市区及其周边地区；它不是以生产木材为主要目标，而是以改善城市生态环境，促进人们健康、提高生活水平为目的。城市森林有着丰富的内涵：它是以城市为载体，以森林植被为主体，以城市绿化、美化和生态化为目的，以人为本，森林景观与人文景观有机结合，改善城市生态环境，加快城市生态化进程，促进城市、城市居民及自然环境间的和谐共存，推动城市可持续发展。     

浅议城市森林

针对城市普遍存在的人口、能源、资源和环境污染等问题，通过阐述城市森林的概念、范围和效益，揭示了城市森林在创造无污染或少污染的优美舒适城市生活环境中的作用和效应，呼吁社会各界重视城市森林的研究和发展，同时提出了发展我国城市森林的几点初浅看法。     

城市森林总量需求与实现途径：以徐州市为例

城市森林的功能—需求可以划分为全球气候、市域国土安全、市域公共安全、基本生活环境和高级精神需求5个关系域,其中碳平衡需求是确定1个城市森林需求总量的主要因子,居民生活水平和森林类型结构的变化对城市森林总量需求影响极大。现行城市绿地（城市森林用地）标准可以满足人年均消费1万元对城市森林总量的需要,当人均年消费1.7万元以上时,（理论上）森林覆盖率需要50%以上。仅靠增加城市森林总量来满足居民生活水平不断提高所带来的高碳排放是难以实现的,必须在增加城市森林数量、改善城市森林结构、提高城市森林质量的同时,增加对市区外辖县森林建设的投入。     

森林城市的低碳措施规划探讨——以安徽池州为例

分析低碳森林城市层次与构成及城市森林的直接减排、间接减排和增加生态容量的低碳效应;分别从城市森林建设、城市低碳生活、城市低碳交通、城市低碳文化、低碳城市规划布局、城市低碳经济等六个方面探讨实现低碳森林城市的措施与建议。     

生态学视角下森林城市规划建设问题浅析

城市化进程影响着居民的生活环境,对城市生态系统也产生重要的影响.城市森林是城市生态系统的主体,城市森林的建设影响着人居环境.文章从生态学角度上,阐述了城市森林树种选择与配置以及城市森林生态系统服务等问题,为建设人与 自然和谐的森林城市提供借鉴.     

在第三届中国城市森林论坛开幕式上的讲话

今天，来自国内外城市的市长们、各省林业主管部门的负责同志和从事城市林业建设理论研究的专家学者们及新闻界的朋友们，大家坎聚美丽星城——长沙，交流城市森林建设的新经验，研讨城市森林建设的新理论，畅谈城市森林建设的新思路，大力宣传城市森林建设对构建和谐城市的重大意义，这对于进一步提高我国城市森林建设与管理水平，加快我国城市森林建设步伐，推动我国城市经济社会走上可持续发展道路、促进构建和谐城市将会产生积极的作用和深远的影响。     

生态学理念在城市森林景观规划中的应用探讨

对城市森林作用及城市生态环境的特殊性进行分析的基础上，运用生态学原理进行城市森林景观规划，提出了城市森林景观规划建设的原则和方法，对我国正在开展的城市森林规划与建设具有理论和实践意义。     

浅谈平顶山市森林资源与城市生态文明建设

城市森林是指在市域范围内以改善城市生态环境,满足经济社会发展,促进人与自然和谐为目的,以森林和树木为主体所构成的环境。森林是孕育人类文明的摇篮,它能有效改善城市生态环境,维护城市生态平衡。发展城市森林是增强城市现代化建设的重要标志。城市与森林和谐共存,人与自然和谐共处,是当今世界生态化城市的时代潮流和发展方向。随着城市化进程的不断加快,森林环城、临水相依成为一种新的城市建设和城市森林发展的必然趋势。大力发展城市森林对提升城市生态文明建设,改善人居环境,提高人民群众生活质量具有重大意义。     

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.