城市绿地空气负离子相关研究——以上海公园为例

通过测量上海主要公园绿地的空气正、负离子、下垫面热辐射温度、森林覆盖率及生物多样性的指标,研究分析了城市绿地的空气清洁度指数(CI)与其影响因素的相关关系。结果发现,上海仅有不到60%的公园空气负离子浓度达到一般城市公园水平;空气清洁度与热辐射温度之间存在指数负相关;空气清洁度与森林覆盖率之间存在指数正相关;空气清洁度与生物多样性之间亦有较强的正相关。       

打造江北绿色明珠——山东聊城大学校园绿化纪实

聊城大学总面积210万m2,校园绿地面积94万m2,绿地率45%,绿化覆盖率达55%以上。其中,草坪51万m2,树林25万m2,乔木2万余株(树木种类48科,103属,160种),有人工湖3处,水面8万多m2,初步实现了校园品种多样化、生态化、园林化的目标,为创造适宜师生学习、工作和生活的生态型校园打下了良好的基础。曾多次获得"山东省绿化先进单位山东省花园式单位""山东省绿化奖章"等荣誉称号。2008年又获得了国家级最高绿化荣誉称号——全国绿化模范单位",且为山东省高校唯一获得此殊荣的学校。       

无锡城郊城市森林建设的思考

无锡城郊地区包括锡山区、惠山区、滨湖区、新区,总面积12.68万hm2,2006年底森林总面积2.49万hm2,森林覆盖率19.6%。该地区是我国最具经济活力的地区之一,城市化进程相当快,城市人口增加和城区面积扩展迅速,同时农业用地和农村人口锐减,呈明显"乡退城进"态势,再加上市域只有两个生态圈,即建成区与城乡结合部,而无通常意义上的城市远郊近自然森林生态圈,城市生态质量"先天"不足。超前作好城郊城市森林规划与实施具有特殊性和紧迫性。       

花园式住宅小区——瑞景新村

瑞景新村地处厦门最高峰云顶岩北麓,依山望海,环境优美,系国家建设部住宅建设试点小区,2001年荣获福建省第一批省级花园式单位荣誉称号。瑞景新村占地面积15.3万m2,建筑面积20万m2,建有住宅1742套,内设幼儿园、小学和农贸市场,绿地面积6.4万m2,建成区绿化覆盖率41.8%。       

合肥市主要城市景观林群落类型及结构研究

研究合肥市区不同功能区景观林组成与结构,共记录102个样方。结果表明:景观林主要组成种有111种,分属45科、81属;主要优势种是香樟、枫杨、水杉、杨树、桂花、石楠等;不同功能区景观林树种相似性系数分别为0.4(公园与居住区)、0.24(高校与居住区)、0.22(公园与高校);林分平均密度560株/hm2,平均基盖度18.83 m2/hm2,平均胸径16.99 cm,平均树高10.13 m,均为正态分布。群落类型可归纳为5个植被型、16个群系及69个群丛,以落叶阔叶型与常绿落叶阔叶混交型为主。建群树种主要有香樟、广玉兰、女贞、雪松、水杉;群落外貌较整齐,树木整体较为健康,景观效果较佳;但层次结构、树种多样性不高,应丰富树种,增加群落的垂直层次,采用近自然经营。       

上海市古树资源特征研究

上海市现存古树1 369株,隶属36科51属63种,其中,银杏的数量最多,达485株,其中7株1 000年以上,年龄最长的达1200年。古树中,乔木类树种最多,其次是小乔木,灌木和藤木类最少;古树主要分布在机关庭院、公园、郊区和道路。上海的古树资源温带成分占总属数的49.0%,热带成分占35.3%,具有温带与亚热带过渡区分布特征;并拥有较多的孑遗种、古老种、特有种和外来种。       

绿色廊坊

近年来,河北省廊坊市委、市政府坚持树立和落实科学发展观,牢固树立绿色就是生命力、绿色就是竞争力的理念,以"园林式、生态型、现代化"为城市定位,连续六年组织开展了"营造城市森林、造福廊坊人民"社会公益活动,大力推进城市生态建设,精心打造"绿色廊坊"城市品牌。截至2004年7月,市区共植树754万株,其中乔木254万株,新增绿地117万m2,城市绿化覆盖率达到42%,绿地率达到36%,人均公共绿地面积达到11m2,全年空气质量指数二级以上天数达到310天,初步实现了"城在林中,林在城中"的目标。       

热爱森林的瑞典人

瑞典是北欧最大的国家,土地总面积为4100万hm2,其中森林总面积2800万hm2,森林覆盖率达到57%。树种以挪威云杉、欧洲赤松和桦木为主。瑞典林业发达,不仅表现在年产值占全国工业总产值8%的的森林工业,更体现在极高的森林社会价值上。       

江西省峡江县城市森林建设规划

以江西省峡江县城市森林为研究对象,通过对城市森林数量、布局等现状的调查和分析,提出了峡江县城市森林建设总体规划目标、总体布局以及建设内容。研究结果表明:按照规划实施,至2020年峡江县城市森林覆盖率将由2010年的60.5%升至68.0%,建成区绿地率由44.6%升至49.7%,建成区绿化覆盖率由49.9%升至53.2%,人均公共绿地面积由12.2m2升至15m2,城市森林生态效益将得到更大发挥,城市生态环境质量将显著提高。该规划的研究成果也将为其他县级城市森林建设规划提供参考。       

常德市太浮山森林公园野生樱花林

常德市太浮山森林公园野生樱花林面积350hm2,约10万株,有尾叶樱(Cerasus dielsiana)、微毛樱(C.clarofolia)、崖樱(C.scopulorum)、山樱花(C.serrulata)、麦李(C.glandulosa)共5种,花期从2月上旬至3月下旬延续2个月,是目前国内发现的面积最大、种类最多、花期最长的野生樱花林。建议管理部门在重视旅游配套设施建设的同时,将打造国内外最大的野生樱花观赏园列为该公园的建设重点。       

Impacts of temperate lianas on tree growth in young deciduous forests

Lianas are often overlooked in temperate ecological studies even though they are important components of forest communities. While lianas have been shown to damage tropical canopy trees and reduce the growth of juvenile trees, the impact of lianas on canopy tree growth in temperate systems is largely unknown. Growth of trees ≥8 cm dbh was examined over a 9-year period within 50-year old post-agricultural secondary forests in the Piedmont region of New Jersey, USA. Five lianas, Celastrus orbiculatus, Lonicera japonica, Parthenocissus quinquefolia, Toxicodendron radicans, and Vitis species, occurred throughout the forest. Total liana basal area, number of stems, and percent cover within host trees were evaluated to assess liana burdens on 606 previously censused trees. These data were related to tree growth to assess liana impacts. Forest trees were separated based on their dominance in the canopy to determine whether lianas had the potential to influence forest composition. In general, lianas in the forests were fairly abundant, with 68% of the trees having at least one liana present. On average, each tree supported 9.7 cm² of liana basal area and 23% of the canopy was covered by lianas. Most of the variation in tree growth was related to the dominance of trees within the canopy, with canopy dominant and co-dominant trees growing 2.5× more than suppressed trees. Liana basal area and number of lianas stems were not related to tree growth, but liana canopy cover decreased tree growth. However, not all trees were equally affected as canopy cover of lianas only reduced growth in dominant and co-dominant trees. Lianas were most influential on host tree growth in unsuppressed trees when occupying a majority of the canopy, only a minority of forest trees. This suppression was not related to differential liana colonization of canopy trees as all canopy classes supported equivalent liana burdens. Though lianas impacted only a minority of the trees in this system, some liana species, C. orbiculatus and Vitis spp., are still increasing and may pose future risks to forest growth and development.     

Investigation of visitors’ motivation,satisfaction and cognition on urban forest parks in Taiwan

This study conducts a survey on the urban forest parks in Taiwan to assess the benefits and affecting factors. The results show that the larger the area of the park, the higher the degree of satisfaction with the landscape and the status of the plants, and the higher the density of trees, the lower the degree of satisfaction with the scenic view. The shading effect is positively correlated with the diameter of plants at breast height, canopy cover area, and proportion of green coverage. However, higher green coverage is associated with lower satisfaction regarding the scenic view and the uniqueness of the landscape. Most visitors are less satisfied with the area of plants and landscape attractiveness. The study results can be used to evaluate the impacts of setting up urban forest parks. The outcomes also provide guidance for the relevant authorities for sustainable management and future policy making.     

Predicted models for potential canopy rainfall interception capacity of landscape trees in Shanghai,China

This study aimed to build urban green space with environmental functions (e.g., canopy interception of rainfall) and adjust hydrographic balance to some extent for forecasting the potential canopy rainfall interception capacity of landscape trees and the effects on rainfall distribution. The effects of urban green space on interception and runoff reduction have been conceptualized, but not quantified. Therefore, the leaf area index and the water storage abilities of 17 kinds of landscape trees in common use were measured, at Shanghai, and canopy rainfall interception capacity was calculated using the interception formula. The predicted rainfall interception capacity models were established choosing tree morphological characteristics (diameter at the breast height, height, and crown width) as variables. The model test showed that the errors of 12 models were less than 5% between the predicted and the measured data and the errors of four models were within 5 and 10%, with the error for only one model being between 10 and 11%. Also, the study indicated that conifer trees were able to hold more rainfall compared with broad-leaved trees per unit area (k). The results showed that these models could effectively predict the potential capacity of canopy rainfall interception for landscape trees in Shanghai area and were beneficial for species selection in constructing plant communities, aiming to improve the rainfall interception capacity of urban green space.     

Light distribution in scattered-trees open woodlands in Western Spain

We have studied the percentage of radiation transmitted through the tree canopy to the underlying pasture and crops in dehesas of Southwest Spain by means of fish-eye photographs taken at different distances from the tree. Thirty-six trees were studied covering all the diametric classes (0.1–14 m canopy width) of two stands, with mean density of 19 mature trees ha⁻¹. Intercepted light decreased with distance following an logistic curve, indicating a rapid increase in the light availability with distance from the tree. For mature trees, radiation was constant beyond 20 m. Applying a multivariable regression light equation, distance, stem diameter and canopy width explained more than 88% of the light variability for each orientation studied. A simple model was built up from light equations, tree growth curves and allometric relationships. From this model, we have estimated that radiation available for crops and pasture decreased up to 21% due to the presence of trees in a standard dehesa with 24 mature trees ha⁻¹ and 13% of canopy cover. In addition, we have generated different radiation maps of virtual dehesas differing in tree age, density and arrangement, which could be useful to determine optimal tree planting schemes and consequent pruning and thinning regimes.     

泰山古树衰弱死亡原因及保护措施

据调查,泰山现有古树总数为18 198株。其中,正常古树占25.4%,轻衰和中衰古树占古树总数的63.7%,重衰和濒危古树所占比例为9%,死亡古树比例达到1.3%,急需保护古树935株。对187株死亡古树的死亡原因分析结果表明,古树自然死亡比例为2.7%,病虫害致使古树衰弱死亡比例为42.8%,工程建设破坏(建筑施工、修路、水泥硬化等)致死比例为25.7%,污水污物(厕所污染,建筑、生活垃圾)致死比例为8.6%,郁闭致死比例为6.4%。分析查找古树衰弱及死亡原因,采取相应的古树保护措施至关重要。       

广州部分公园的冷岛效应及影响因子的初步研究

结合植被种类和群落结构调查,对广州四个城市公园绿地的温湿度进行自动监测,每1小时一次,连续监测30天,并采用PCA排序法分析广州市公园的"冷岛"效应与植被、公园面积等因子之间的相关性。结果表明:白天公园气温降低值和相对湿度增加值大小排序一致,黑夜的排序则与之相反。白天的月气温降低与公园面积、水体面积和乔木平均胸径呈正相关;月气温降低与乔木密度呈正相关;月、白天、黑夜相对湿度增加与乔木平均树高、乔木平均胸径、水体面积呈正相关。最终得出结论,广州市的城市公园具有显著的降温增湿效应,且日间降温增湿的幅度大于夜间。     

济南市主要公园乔木树种结构及动态

采用抽样调查的方法,对济南市的6个主要公园黄河森林公园、千佛山公园、环城公园、大明湖公园、五龙潭公园、趵突泉公园的树木进行调查。通过树种数、树种丰富度、树种多样性、树种均匀度4个指标对济南市各公园的树种组成结构进行分析,同时通过上述6个公园的树木总数、树木种类和胸径分布关系对公园树木结构特征进行分析。结果表明,大明湖公园的树种数最多,趵突泉公园的树种丰富度最大,千佛山公园的树种丰富程度最高,黄河森林公园树种最均匀。国槐(Sophora japonica)出现比例最高,占全部树木的10.69%。前20位树种总数占全部树木的75.06%,树木的数量构成具有明显的聚集性,出现少数树种主导整个群落的现象。从树木株数随胸径的分布看,同天然林存在差异,表现为近似的抛物线状。从不同胸径等级树种数分布上看,小径级的树种数多,大径级的树种数少,反映出济南市城市公园树种丰富度不断增加的趋势。       

封山育林对杂谷脑河干旱河谷区植被恢复的影响

本文通过对干旱河谷封山育林区域与未封山育林区造林苗木生长状况和灌草群落特征对比,开展封山育林对干旱河谷区植被恢复成效研究。研究结果表明:在相同坡向和海拔梯度上,封山育林区造林苗木平均保存率和树高净生长量均极显著性高于未封山育林区,其差值变化幅度分别为21%(阴坡Ⅰ)~31%(阴坡Ⅲ)和42.7%(阳坡Ⅰ)~59.7%(阳坡Ⅱ);灌草平均盖度和高也表现为封山育林区高于未封山育林区,灌木和草本平均盖度差值变化幅度1.1%(阳坡Ⅰ)~26.7%(阳坡Ⅱ)和2.2%(阳坡Ⅰ)~18.5%(阳坡Ⅱ)之间;灌木和草本平均高度差值变化幅度8.2%(阳坡Ⅰ)~53.5%(阴坡Ⅲ)之间和17.9%(阴坡Ⅲ)~28.9%(阴坡Ⅱ)之间。     

Enhanced transpiration in response to wind effects at the edge of a blue gum (Eucalyptus globulus) plantation

In Australia, tree planting has been widely promoted to alleviate dryland salinity and one proposed planting configuration is that of strategically placed interception belts. We conducted an experiment to determine the effect of tree position in a belt on transpiration rate. We also assessed how much the effect of tree position can be explained by advection and environmental conditions. Daily transpiration rates were determined by the heat pulse velocity technique for four edge and 12 inner trees in a 7-year-old Tasmanian blue gum (Eucalyptus globulus) plantation in South Australia. Various climatic variables were logged automatically at one edge of the plantation. The relationship between daily sap flow and sapwood area was strongly linear for the edge trees (r2 = 0.97), but only moderately correlated for the inner trees (r2 = 0.46), suggesting an edge effect. For all trees, sap flow normalized to sapwood area (Qs) increased with potential evaporation (PE) initially and then became independent as PE increased further. There was a fairly close correlation between transpiration of the edge and inner trees, implying that water availability was partially responsible for the difference between inner and edge trees. However, the ratio of edge tree to inner tree transpiration differed from unity, indicating differences in canopy conductance, which were estimated by an inverse form of the Penman-Monteith equation. When canopy conductances were less than a critical value, there was a strong linear relationship between Qs of the edge and inner trees. When canopy conductances of the edge trees were greater than the critical value, the slope of the linear relationship was steeper, indicating greater transpiration of the edge trees compared with the inner trees. This was interpreted as evidence for enhancement of transpiration of the edge trees by advection of wind energy.