林网化与水网化——中国城市森林建设理念

建设森林城市要求有足够的森林面积和通畅的水循环系统。本文以上海为例提出在人多地少与水系统不很通畅的中国发展城市林业必须走林网化和水网化的道路。为探索具有中国特色的城市森林发展新理念。作者从理念的内涵、依据、过渡和国内外比较研究等几方面作了阐述。       

泉州中心市区城市森林建设与发展

文章针对泉州中心市区城市森林建设现状及其存在的问题,以"近自然森林"的理念和模式,提出了解决现实问题的措施和建议,旨在为构建融山、水、林、城于一体,寓社会价值、经济价值、生态价值协调统一的泉州中心市区现代化城市森林体系,提供可持续发展的理论和实践依据。       

城市特色森林建设思考与实践

城市森林的概念以及内涵表明了城市特色森林建设是当前提高城市园林绿地的生态质量重要途径,本着城市园林绿地的各种效益平衡点出发,依据城市5大类园林绿地的不同功能侧重作为8大类城市特色森林模式建立的切入点,明确了不同类城市特色森林建设的内容、适用范围以及主要措施,最后通过案例的阐释进一步表明了特色森林模式运用的可行性和有效性。       

因地制宜建设特色城市森林——以无锡市城市森林建设总体规划为例

以无锡市城市森林总体规划为例,探讨因地制宜的特色城市森林规划建设战略;以创建特色森林城市为目标,以无锡市自然、文化和城市发展3方面为重要内容,提出依水建林、森林生态建设、森林生态网络建设和森林生态文化景观区建设4大规划战略。       

城市森林规划的现状与发展

分析了城市森林规划在中国发展的背景,通过案例分析,总结比较了英美两国城市森林规划的特点以及中国城市森林规划的特点,从城市森林规划的范围、与城市绿地系统规划的关系、规划对象、内容、方法、城市森林的多功能问题、协调问题、规划实施和规划立法九个方面探讨了中国城市森林规划的发展。       

宁波市森林城市建设总体规划

文章分析宁波市自然概况、城市森林现状及其城市特色,应用景观生态学的原理,结合"核、环、轴、楔、园、链"结构模式,提出了宁波市城市森林系统结构;建议加强城市绿心和生态保护带建设,改善城区森林绿地质量,提供城市生态资源氧库,保持森林生态系统的连续性和多样性,演绎城市文脉,引导城市环境与郊区自然环境共生与交融,建设具有山水特色的森林城市。       

城市森林经营方案编制提纲

通过对国内外城市森林建设和理论研究实践的分析,论述了城市森林经营方案编制的重要性和必要性,提出城市森林经营方案编制的指导思想、基本原则和重要内容,着重介绍了城市森林经营方案编制的几个关键技术和对策措施。       

以生态学原理创建国家森林城市 建设优美人居环境

阐述城市森林与城市林业的概念、城市与城市森林的范围、森林城市的涵义与创建森林城市的意义。文章的重点是以生态学原理创建森林城市,主要生态学原理是生物多样性导致生态系统稳定性原理、模拟天然林群落结构——系统性原理以及自然选择与生态适应原理,提出应用景观生态学原理使城市森林一体化,体现"岛屿生物地理学"理论,通过生态系统食物链的调节作用控制森林病虫害。       

构建上海城市水绿生态体系

本文从上海城市绿化和水利问题的现状分析出发,运用城市生态发展理论,提出构建上海城市水绿生态体系,建议优化上海城市水网、林网结构,保护城市现有湿地资源和构建人工森林湿地。       

成都市城市森林规划(纲要)

以建设国家森林城市为契机,坚持城乡一体化发展,建立布局合理、绿量充足、生物多样、景观优美、特色鲜明、功能完善的城市森林生态系统,把成都建设成为"创业环境最优、人居环境最佳,综合竞争力最强"的中国中西部特大中心城市和森林生态城市。并将城市森林建设纳入修编的《成都历史文化名城保护规划》和《成都市城市总体规划》。       

城市森林水土流失率的研究

运用水土流失的新指标水流失率、水土流失率来考察城市降水水流失率和水土流失率。并对北京、伦敦的城市森林和河南长江流域山区水土保持林的水流失率进行了计算比较。得出水流失率、水土流失率是考察城市森林水土流失较好的指标。     

Daily transpiration rates of woody species on drying soil

Among annual plants, daily transpiration rates, expressed as a fraction of volumetric soil water content available for transpiration, show a common pattern in response to soil drying. Initially, as soil dries, there is little decrease in transpiration rate until water availability has fallen to about one third that at field capacity. With further soil drying, relative transpiration rate decreases in a more-or-less linear fashion until all available water has been used. Data previously obtained for perennial woody species have often been confounded by different methods for determining available soil water. In this study, we investigated the daily transpiration response to soil drying in five woody perennial species: Thuja plicata Donn ex D. Don, Acer rubrum L., Robinia pseudoacacia L., Hibiscus sp. and Ibex aquifolium L. Transpiration was unaffected by soil drying until the initial estimated transpirable soil water fraction had decreased to between 0.23 and 0.32 of that at field capacity. Beyond this point, transpiration rate declined linearly with available soil water fraction until reaching one fifth the rate observed in well-watered plants. With further soil drying, the relative transpiration rates remained between 10 and 20% of that observed in well-watered plants. Maintenance of transpiration at these rates with further soil drying was hypothesized to result from contributions to transpiration of water stored in plant tissues. After taking tissue water storage into account, it was estimated that transpiration was curtailed as the available soil water fraction fell to between 0.26 and 0.37 of that at field capacity, which is comparable to values reported for annual crop plants.     

A comparison of root growth dynamics of silver maple and flowering dogwood in compacted soil at differing soil water contents

Many bottomland tree species are tolerant of compacted soil and perform well in urban environments; however, the mechanism underlying this tolerance is unknown. Increased soil water content has been shown to alleviate some of the effects of soil compaction on plant growth, presumably because increasing soil water reduces soil strength. We hypothesized that tree species tolerant of very wet soils would have opportunities for root growth in compacted soil when high soil water contents reduced soil strength, whereas species intolerant of bottomland conditions would not. We tested this hypothesis on flowering dogwood (Cornus florida L.), a mesic species intolerant of inundation, and silver maple (Acer saccharinum L.), a bottomland species. Seedlings of both species were grown in pots for 21 and 30 days, respectively, in a growth chamber in native loam soil maintained at various combinations of soil strength and soil water tension. Downward root growth rate decreased in response to increasing soil strength in both species. At low soil strength (0.6 MPa), downward root growth rate of dogwood seedlings slowed when soil was either excessively wet or dry, whereas root growth rate of silver maple seedlings increased linearly with soil water content. In moderately compacted soil (1.5 g cm(-3) bulk density), silver maple seedlings had greater root growth rate, root length per plant, and ratio of root length to root dry weight in wet soil (0.006 MPa soil water tension) than in moist and dry soils (0.026 and 0.06 MPa, respectively), even though mean oxygen diffusion rate (ODR) was only 0.28 &mgr;g cm(-2) (SE = 0.05). No such effect was detected in highly compacted soil (1.7 g cm(-3) bulk density) in either species. Mean ODR showed a weak positive correlation with soil water tension (r = 0.40, P = 0.07), but was unrelated to soil strength. We conclude that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity.     

失水程度对苗木质量的影响

失水程度对造林成活率和初期生长量有显著影响,失水超过一定程度苗木即失去生机     

马尾松混交林持水性能的研究

通过对南方陡坡山地开展马尾松不同混交林林分类型持水能力研究,结果表明,马尾松与阔叶树木荷、火力楠混交,林分持水能力比马尾松与杉木混交及马尾松纯林强,针阔混交林能较大提高土壤涵养水源和保持水土的能力,使土壤得到较好改良,而营造针叶林则土壤持水能力低,易发生水土流失。建议南方陡坡山地采用针阔混交造林,尽量避免针叶纯林。     

油松人工林水分平衡与蒸散特点的研究

油松(Pinus tabulaeformiss Carr)是华北地区的重要造林树种之一,在许多地方由于水分缺乏而生长不良。为此,在1 983-1984年,我们选择有代表性的中龄人工林,应用水文学方法     

苗木枝接保湿方法研究

枝接是苗木嫁接的主要方法之一,一般在春季进行。枝接时,为了节省接穗,一般将1 根枝条剪截成若干个接穗,嫁接后,由于接穗顶部切口暴露在空气中,易失水枯萎,降低生活 力,影响嫁接成活。2000年春季开始,在果树苗、绿化树苗上开展枝接保湿方法研究。结果表 明:用塑料薄膜封盖接穗顶部切口减少接穗水分蒸发8%～10%,平均嫁接成活率达96.4%。     

江苏海岸带造林特困地育林新技术的研究

根据江苏海岸带造林特困地盐多肥少、风害潮灾、土旱地疹的特点，以I－69杨为造林树种，对海岸带造林特困地的造林方法，配套技术，管理措施等方面进行了较为深入的试验和研究，形成了海岸带造林特困地高产优质高效简化育林新技术，即在海岸带造林特困地上，扦插造林不但可操作性强，而且造林成本低；扦插造林前对插穗用保水生根杀虫剂处理，造林成活率可达85％左右，扦插时辅施棒肥，可长效地促进林木高生长和径生长；幼林抚育管理措施可简化为覆膜压草。     

Predicting the decline in daily maximum transpiration rate of two pine stands during drought based on constant minimum leaf water potential and plant hydraulic conductance

The effect of drought on forest water use is often estimated with models, but comprehensive models require many parameters, and simple models may not be sufficiently flexible. Many tree species, Pinus species in particular, have been shown to maintain a constant minimum leaf water potential above the critical threshold for xylem embolism during drought. In such cases, prediction of the relative decline in daily maximum transpiration rate with decreasing soil water content is relatively straightforward. We constructed a soil-plant water flow model assuming constant plant conductance and daily minimum leaf water potential, but variable conductance from soil to root. We tested this model against independent data from two sites: automatic shoot chamber data and sap flow measurements from a boreal Scots pine (Pinus sylvestris L.) stand; and sap flow measurements from a maritime pine (Pinus pinaster Ait.) stand. To focus on soil limitations to water uptake, we expressed daily maximum transpiration rate relative to the rate that would be obtained in wet soil with similar environmental variables. The comparison was successful, although the maritime pine stand showed carry-over effects of the drought that we could not explain. For the boreal Scots pine stand, daily maximum transpiration was best predicted by water content of soil deeper than 5 cm. A sensitivity analysis revealed that model predictions were relatively insensitive to the minimum leaf water potential, which can be accounted for by the importance of soil resistance of drying soil. We conclude that a model with constant plant conductance and minimum leaf water potential can accurately predict the decline in daily maximum transpiration rate during drought for these two pine stands, and that including further detail about plant compartments would add little predictive power, except in predicting recovery from severe drought.     

杉木人工林的温湿效应

以连续多年的定位测定数据,研究了杉木人工林的温湿效应.结果表明:由于杉木林冠层的作用,使杉木林内形成了温度变化平缓,林冠层对地表温和土温的调节作用远大于气温;由于冠层的阻滞作用,使林内风速很小,乱流交换较弱,林木蒸腾蒸发的水气不易散失,造就了林内水气充沛、空气湿润的特征;杉木林内显热能的日平均波动在2%,杉木林内环境的潜热能占总温湿能的8%左右;杉木林具有这样的温湿特征是杉木林的结构特征、杉木林生理功能与环境相互作用的结果.