城市森林型绿地的植物景观改造设计初探——以怀柔城南森林公园为例

北京市在城市森林型绿地建设的大背景下,开展了一系列此类项目的建设。笔者在工作中参与了怀柔区2018年"城市森林"建设项目——怀柔城南森林公园的规划设计工作,该项目场地内存在大量现状造林地块,对城市森林建设中的近自然植物景观营造带来较高的难度。考虑到城市森林建设趋势和城市化区域内现状林存在的普遍性,笔者认为城市森林型绿地建设中对植物景观的改造设计十分重要,并以此为契机对其进行研究。依托规划实践,提出理结构、调林相、建群落、注文化四大策略。笔者以此为基础,初步完成了怀柔城南森林公园植物景观的改造设计,为后续城市森林型绿地建设过程中植物景观改造设计提供了一定的参考依据。     

生态城市绿地建设的六原则

绿地要与城建项目的规划和建设同步或优先，规划中要尽量保留原有的自然和文化景观．把城市建设对生态环境的干扰和破坏降低到最低程度。在植物景观多样性建设计中，要合理地对绿地整体空间进行生态配置，发挥绿地水循环、气候调节、降低污染等功能，追求整体的系统生产力，健全景观生态结构。同时．要注意增加绿量。我国绿色生态城市建设，绿地率要求在40％以上。     

新农村绿地景观建设研究进展与可持续发展策略

绿地景观是新农村建设的重要内容,我国新农村绿地景观是一个新兴的研究领域。该文通过对我国新农村绿地建设的现状进行分析,从新农村的绿地景观特征、绿地分类、绿地景观综合功能和绿化规划等4个方面,剖析了我国新农村绿地景观研究的主要内容、状况和存在的问题,指出了未来的研究趋势和可持续发展策略与建议,以期为我国新农村绿地景观的建设提供理论参考。     

南昌市花园城市建设中存在的问题及对策措施

南昌市花园城市建设中存在绿地发展不平衡、建筑密度过大、绿地结构不合理、缺乏防护林、对绿量与景观质量的综合考虑不够等问题,据此提出了科学规划、加强旧城改造、增强绿地域特色、重视防灾功能等对策措施。     

武汉市江岸区生活型道路绿地景观研究

指出了城市道路绿地是城市绿地系统的一个重要组成部分,也是城市居民日常接触最多的绿地景观类型,在城市环境建设中扮演举足轻重的角色。以武汉市江岸区生活型道路绿地景观为研究对象,从物种丰富度和绿化配置形式两方面对其进行全面了分析,并总结了现状存在的问题,有针对性地对武汉城市生活型道路绿地景观建设提出了改进建议,以便为武汉市今后的道路绿地发展提供参考。     

通道县城市森林及绿地调查

对通道县城市公共绿地、生产绿地、防护绿地、风景绿地、道路绿地、居住区绿地和单位附属绿地、城市森林面积、森林蓄积进行了调查,探讨了城市森林及绿地存在的问题,提出了通道县城市森林发展的建议。     

绿化隔离带的景观规划

绿化隔离带是城市有生命力的重要基础设施,在近自然景观的规划建设中需从建设生态型森林城市和林业可持续发展角度,保护和恢复隔离带内的自然斑块,优化绿地景观的空间布局和功能结构,充分发挥其生态、经济和社会效益,维护     

基于GIS和Fragstats的青神县城区绿地景观格局研究

分析青神县绿地系统景观格局特征和存在问题,为青神县创建国家森林城市提供理论依据和参考。以2018年遥感影像和青神县主城区绿地系统图为基础,通过对遥感数据进行融合、图像增强等处理,采用面向对象法提绿地信息。并结合现场调查,对绿地类型进行了科学分类,并基于Fragstats景观处理软件定量分析了青神县中心城区绿地系统的景观结构及景观格局。结果:(1)青神县绿地系统中面积最大的是区域绿地(其他绿地),占全部绿地的35.08%。公园绿地面积较小,所占比例不大(19.10%)。(2)青神县总体景观形状较为规则和简单,有利于青神县城市景观的规划利用和管理。(3)区域内景观整体连通性较好,人为干扰或自然破坏较小,但各景观类型之间的连通性和空间上的聚集度均不强。绿地景观之间的连通性和聚集度不强,影响生物多样性的保护及自然生态过程。青神县在创建国家森林城市过程中,应控制人工景观占比,增加城市绿地,尤其要增加公园绿地的面积并合理均匀布局,并增加通道绿化,将城市中逐渐岛屿状化的大型生物栖息地有机联系起来,构筑连续的生态绿地网络,保护动物在城市内部的迁徙通道,增加景观的连续性。     

青神县城市森林结构特征

森林的结构决定功能,功能反映结构。调查青神县城市森林结构现状,分析存在的问题和空间规律,为森林城市的规划和城市森林的建设提供基础资料和参考依据。将青城县城区的绿地分为公园绿地、道路防护绿地和附属绿地三大类。对这三大类绿地内的木本植物进行全部或抽样调查。分析物种组成特征,计算物种多样性、径级结构和冠幅结构等。结果:(1)青神县城市森林的木本植物一共有96种(不含竹林湿地公园),隶属于45科76属。(2)城市森林绿化木本植物中常绿植物明显占优势,常绿植物物种数是落叶物种数的1.88倍。(3)物种多样性水平以附属绿地最高,其次是公园绿地,街道防护绿地最低。(4)从观赏部位来看,以植株造型和观花物种占优势,分别占总物种数的36.73%、29.59%,色叶类物种数占13.27%。(5)乔木物种以胸径10～20 cm、冠幅2～4 m的最多,均占50%以上。青神县城市森林物种多样性还不够丰富,在今后的城市森林建设中,应以乡土乔木树种为主,合理搭配灌、草物种,并增加色叶、观花、观果类植物的种类和数量。     

瘦西湖风景区森林生态系统建设与规划

瘦西湖风景区森林生态系统建设与规划是城市森林生态体系研究与示范扬州试验点的重要组成部分，是实现风景区可持续发展的的重要条件。介绍了利用历史遗存植物造景、坚持乡土树种地被植物应用、加强生物多样性原则、开发水生湿地植被景观、推进生物防治管理等景区森林生态系统建设的基本原则；并就自然植被资源保护、湿地植物景观体现以及生态绿地模式建设等设想，对景区森林生态系统可持续发展的建设目标进行了初步规划和探讨。     

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.