Influences on the use of urban green space – A case study in Odense,Denmark

Increasing the use of urban green space has appeared on the political agenda, primarily because increased use is expected to improve the health and well-being of the urban population. Green space is contributing to restoring mental fatigue, serving as a resource for physical activity, reducing mortality and reducing the level of stress.However, knowledge and experience on how to implement this agenda are scarce. In this paper, we use a socio-ecological model as framework when studying influences on the use of respondents’ nearest urban green space in the Danish city of Odense. Data were obtained from a survey sent to 2500 randomly selected adult residents within the central part of the city. We tested the relative importance of different factors on the frequency of use of the nearest urban green space by using a multivariate logistic regression model. The results show that almost half of the respondents did not use their nearest green space the most. Whether or not respondent used their nearest green space most depends primarily on area size, distance to the area and factors that are likely to express a reduced mobility; old age, young children and poor health.If the nearest urban green space also is the most used green space, having a dog is the only factor that significantly increases the frequency of use. Further research is needed to determine what it is that makes people use an area more, if the basic conditions of a reasonable size (>5 ha) within a reasonable distance (<600 m) are fulfilled.     

The utility of ancient forest indicator species in urban environments: A case study from Poznań, Poland

We aimed to assess the impact of land-use structure on AFIS occurrence and evaluation of these bioindicators in urban conditions. We compiled data about forest continuity based on archival maps and forest management plans; floristic records of 79 AFIS occurrences were collected within a 1 × 1 km grid and land-use form structure in Poznań (W Poland). We tested fidelity of AFIS using χ² tests and effects of land-use structure using random forest models. We also checked spatial autocorrelation and its impact on AFIS distribution patterns within old and recent forests, using spatially explicit generalized linear models. We found a strong relationship between AFIS number per grid square and fraction of forests and waters in land-use structure. Relationships between AFIS distribution and land-use shows that AFIS are a good proxy describing human impact or an urbanity gradient. AFIS number per grid square shows small, but significant positive spatial autocorrelation, which suggests possibilities of migration into new forests. AFIS, treated as a bioindicative group of species, may be a useful indicator of landscape and land-use structure transformation in urban environments. Occurrence of many AFIS that are endangered at the city scale indicates the need for conservation of old forests in urban areas, to preserve biodiversity in urban environments. Thus, AFIS may act as indicators of old forests with high conservation value in cities, which need special protection.     

Assessment and optimization of green space for urban transformation in resources-based city – A case study of Lengshuijiang city,China

Urbanization in China has changed gradually from production-oriented to consumption-oriented in recent years. Comfort and accessibility of green infrastructures effect the rate of urbanization and transformation. A well designed urban green space system is an essential part of the urbanization process. In this paper, the urban green space of Lengshuijiang city was assessed both qualitatively and quantitatively using data of field survey and high resolution remote sensing. In the study area, green space coverage was 37.14%, green space percentage was 33.45% and per capita park green space was 16.25 m². The high green space coverage suggested that there were ample potentials for further urban transformation. Within a 30 min service radius of existing green space, total service area was 204.49 ha, which accounted for 16.26% of the study area. A high proportion of the green space was made up of urban parks which were unevenly distributed across the study area. A green space optimization strategy, aimed at improving green space quality and accessibility, was proposed. After optimization, total service areas within the 30 min service radius will increase to 492 ha (39.12%), an increase of 22.86%. Our study demonstrated that combining qualitative and quantitative methods is an effective and reliable way for green space assessment and reliable and can be used for urban green space planning and management for small resource-based cities like Lengshuijiang in its process of urban transformation.     

Mapping of urban roadside trees – A case study in the tree register update process in Helsinki City

This case study describes a method for utilizing leaf-off airborne laser scanning (ALS) data for mapping characteristics of urban trees. ALS data were utilized to detect and update all street trees in the tree inventory of the City of Helsinki, Finland. The inventory consists of roughly 20,000 street trees with mean diameter at breast height (DBH) of 24 cm and mean height of 10.6 m. The large number of trees makes the manual updating process very laborious. The automatic mapping procedure presented in this paper detected 88.8% of all trees in the inventory. Tree height was predicted with root mean square error (RMSE) of 1.27 meters and tree DBH with RMSE of 6.9 cm. The presented method provides a practical and cost–effective tool for the mapping of urban tree characteristics. The cost–efficiency was further enhanced because the used ALS data were originally collected for other urban planning purposes.     

Visitors’ heterogeneous preferences for urban park management: The case of a city park in Oulu,Finland

Utilizing survey data collected using a combined travel cost – conditional behavior method, the aim of this study was to analyze the heterogeneity of preferences among the residents of a city in Finland for the services of an urban park and its stream network. More specifically, by analyzing different behavioral responses to potential changes in ecological, cultural, and commercial services, we identified different groups of visitors to the park with a latent class model. A notable result regarding the demand for services in different classes was that low-income people valued the park more than high-income respondents, making improvements in the park’s recreational potential a successful social project. We found two latent classes, the main distinguishing factor of which was the preferences associated with increasing the number of events in the park. Adding events did not increase the benefits for the first class, but for the second class it did. In relation to class membership, if visitors usually visited the park alone or if they walked or cycled to the park, this increased the likelihood of belonging to a particular visitor group. In addition, we assessed how a possible increase in services affected the recreational value of the urban park for the city’s residents. We found that both the total and net value for different urban groups depended on three factors, i.e., the number of visits, the recreational value of a visit, and the proportion of people in each visitor group. We also used the results of the study to assess the profitability of a construction and management project in the park and found that the project was socially very profitable. Although our study examined a specific park in Finland, its results could also potentially be used when planning the management of other urban parks.     

Uptake and use of biodiversity offsetting in urban planning – The case of Sweden

Globally, biodiversity offsetting is used to balance negative impacts on biodiversity and ecosystem services caused by exploitation. In Sweden, there is an increasing interest in biodiversity offsetting in urban planning. However, there is limited understanding about the use of the concept in a municipal context. This study aims to examine and critically reflect on the uptake and use of biodiversity offsetting at a strategic level in urban planning in Sweden. We study urban planning documents, and included Sweden’s 290 municipalities in the study. The result shows that more than 50% of Sweden’s municipalities mention biodiversity offsetting in their planning documents, targeting both regulatory offsetting of protected areas and voluntary offsetting of urban green space. The uptake is highest in urban areas experiencing high exploitation pressure, and many municipalities include both biodiversity and ecosystem services in their strategic work with offsetting. Most municipalities do not relate to the mitigation hierarchy (avoid, minimize, restore, offset), nor the goal of no net loss of biodiversity and ecosystem services. There is an ambiguity in the translation between losses and offsets, i.e. what type of offsetting (like-for-(un)like), what replacement ratios, and where to place the offsets. Few municipalities have developed processes, guidelines, strategic plans, etc., to integrate offsetting into the planning process. We conclude that the uptake of biodiversity offsetting is substantial, but with a fragmented, and often immature use in relation to ecological knowledge, and the planning process. We argue that, to develop biodiversity offsetting into an approach that delivers sound outcomes for nature and people in urban planning, municipalities must have a capacity in terms of organisational structures and resources.     

Tree establishment practice in towns and cities – Results from a European survey

A working group within the European Union funded COST Action E12, “Urban Forests and Trees”, carried out a survey between 1999 and 2001 to study current tree establishment practice in European towns and cities. An extensive questionnaire requesting information on the urban area, selection of tree species, establishment and aftercare practices and the main damaging factors was sent to tree professionals in urban areas in each of 17 countries.Indicators such as the relationship between the urban population and the number of street trees were used to compare urban areas. While most central European cities have a ratio of 50–80 street trees per 1000 inhabitants, the tree density was as low as 20 street trees per 1000 inhabitants for Nice. Often only a few species are planted and this may give cause for concern, since species diversity is considered an important factor in increasing the resilience of the urban tree population to abiotic and biotic stresses.The planting of larger street trees of 20–30 cm circumference, usually with hessian-wrapped rootballs, is becoming increasingly common practice. However, some countries report the use of mostly bare-rooted stock of much smaller trees (less than 12 cm circumference). Establishment costs for street trees range from less than 200 Euro to over 1500 Euro each. Poor site conditions, and impacts such as utility trenching are considered to be major restrictions to healthy tree life. Vandalism affects up to 30%of newly planted street trees in some towns and cities.Overall, the survey reveals large differences in tree establishment and management practices among European cities. There is a need to provide urban tree managers with guidance on good practice for tree selection and establishment based on empirical information. The survey was a first step towards collecting the necessary urban forest information from across Europe.     

Elevational treeline and forest line dynamics in Norwegian mountain areas – a review

Purpose

Treelines and forest lines (TFLs) have received growing interest in recent decades, due to their potential role as indicators of climate change. However, the understanding of TFL dynamics is challenged by the complex interactions of factors that control TFLs. The review aims to provide an overview over the trends in the elevational dynamics of TFLs in Norway since the beginning of the 20th century, to identify main challenges to explain temporal and spatial patterns in TFL dynamics, and to identify important domains for future research.

Method

A systematic search was performed using international and Norwegian search engines for peer-reviewed articles, scientific reports, and MA and PhD theses concerning TFL changes.

Results

Most articles indicate TFL rise, but with high variability. Single factors that have an impact on TFL dynamics are well understood, but knowledge gaps exist with regard to interactions and feedbacks, especially those leading to distributional time lags. Extracting the most relevant factors for TFL changes, especially with regard to climate versus land-use changes, requires more research.

Conclusions

Existing data on TFL dynamics provide a broad overview of past and current changes, but estimations of reliable TFL changes for Norway as a whole is impossible. The main challenges in future empirically-based predictions of TFLs are to understand causes of time lags, separate effects of contemporary processes, and make progress on the impacts of feedback and interactions. Remapping needs to be continued, but combined with both the establishment of representative TFL monitoring sites and field experiments.

     

How does enclosed private residential green space impact accessibility equity in urban regions? A case study in Shenzhen,China

Compared with public parks, residential quarter green space (RQGS) is a type of enclosed private green space that is located in residential areas and has higher visit frequency. Generally, in China residential areas with high housing prices have higher quality and more quantity of RQGS. Therefore, the differences in RQGS between residents with different socio-economic status may influence the equity of urban green space accessibility. However, due to the lack of data sources, few existing studies have taken RQGS into account as a part of urban green space supply resources. Based on multi-source geographic big data, this paper takes Shenzhen as the research area to explore the impact of RQGS on the spatial pattern and fair distribution of green space accessibility. The total green space accessibility (TGSA), which includes the accessibility of RQGS, and the public park accessibility (PPA) were calculated using the Gaussian-based two-step floating catchment area method (2SFCA). Using housing prices to indicate the income level of dwellers, bivariate Moran’s I and multiple regression were adopted to explore equity of urban green space accessibility. The main conclusions were: (1) The accessibility of green space increased by 27.97% on average after considering RQGS and ignoring RQGS could underestimate the accessibility of green space, particularly in the residential quarter with high housing prices near the city center. (2) The regression coefficients of housing prices with PPA and TGSA were 0.042 (p < 0.01) and 0.160 (p < 0.001), respectively, indicating that the advantages of high-income groups in RQGS may further exacerbate the inequity of urban green space accessibility. The research conclusions may provide a scientific basis for optimizing the spatial structure of green space in urban areas and ensuring the equitable distribution of green space.     

Impact of urban park’s tree,grass and waterbody on microclimate in hot summer days: A case study of Olympic Park in Beijing,China

Urban heat island (UHI) often cause negative impact and has been linked to heart stroke rate, morality, human comfort, energy consumption and air pollution. Fortunately, urban green spaces have been considered as an effective element to mitigate UHI through their cooling effect. However, further empirical research is necessary in order to efficiently guide the design and planning of urban green space. We observed the impacts of urban park's tree, grass and waterbody on microclimate inside the Olympic park of Beijing during summer days. The results indicated that, on average, the park was 0.48–1.12 °C cooler during the day, as well as increased air humidity 2.39–3.74% and reduced human comfort index 1.02–2.43 to generate more comfortable thermal environment. Urban park's cluster trees with short ground vegetation generated higher cooling effect than single trees, grass and waterbodies; proper irrigation regime enhanced the cooling effect of grasses, even the irrigated grass have similar cooling effect with small waterbody on sunny, windless summer days. Therefore, we advise to increase undergrowth coverage and grass irrigation management in order to take advantage of cooling effect of urban parks.     

How many people should be in the urban forest? A comparison of trail preferences of Vienna and Sapporo forest visitor segments

Differences in trail preferences for social conditions of visitors to forests in Vienna and Sapporo were investigated in 2006 using a standardised image-based stated choice approach. On-site visitors to two comparable peri-urban forests – the Lobau Forest in Vienna, Austria (n=373), and the Nopporo Forest in Sapporo, Japan (n=256) – evaluated the same sets of computer manipulated images depicting 128 trail scenarios with different levels of social stimulation. Latent class segmentations, in three sub-segments of similar sizes, differentiated by partly opposite preferences for social conditions, were derived for both samples. A positive contribution of social stimulation to preferences was found for about 17% of Nopporo and 9% of Lobau respondents, while for close to 50% of Lobau respondents and 38% of Nopporo respondents very low levels of social stimulation were preferred. The results indicate that urban forests should be managed for users with a desire for low social densities as well as a denser social setting providing some levels of social stimulation.     

A contribution to the study of airborne Citrus pollen in Córdoba,southern Spain

Citrus species, and especially oranges, are widely grown in Córdoba (southern Spain) both as ornamentals (Citrus aurantium) and as cash crops (Citrus sinensis). There has been little research into the incidence of orange-pollen allergy in the local population. Given the abundant presence of orange trees in Córdoba, a study was designed to determine local Citrus pollen counts at human height in areas where these trees are densely planted. Although standard aerobiological studies report negligible airborne Citrus pollen counts, the samplers used are located at greater heights and in open areas; as a result, large Citrus pollen grains are not recorded. It was found that when Hirst-type volumetric samplers were placed on the roof of a building – the recommended position for aerobiological research – airborne Citrus pollen counts were very low. By contrast, portable samplers placed at human breathing height recorded very high counts, reaching around 2000 pollen grains/m³ during the peak day. This finding suggests that greater attention should be paid to the potential negative impact on the local population, given that the sparse research has highlighted the allergenic nature of orange pollen. Citrus pollen could have an adverse local health impact in areas where orange-trees are densely planted, particularly given reported cross-reactivity with other pollen types. However, further aerobiological and clinical research into Citrus pollen is required in order to draw wholly reliable conclusions.     

Stress-resistant trees are more common in urban than rural forests: A case study of Cleveland,Ohio’s natural parks

Natural parks are comprised of preserved forested natural areas that are undergoing natural ecological processes. These areas can offer a refuge for local biodiversity and contribute substantially to ecosystem services in both rural areas with relatively low population densities, as well as high-density urban areas. Forested natural parks located in urban areas should experience more stressful environmental conditions than nearby rural areas, yet we know relatively little about how urbanization impacts tree communities within these important natural habitats. To better understand the impact of urbanization on forests, we investigated the species composition, abundance, and diversity of midstory and canopy trees as well as tree seedlings in urban and rural natural parks in and around Cleveland, Ohio. We found that both urban and rural natural parks have similar tree abundance, but midstory and canopy trees as well as tree seedling communities in the urban natural parks included higher abundances of stress-tolerant species compared to rural parks. In addition, this pattern was driven by changes in native tree species, as we observed low abundance of invasive species. More stress-resistant native species in urban areas include Quercus rubra and Prunus serotina, in contrast to rural natural parks which are dominated by Acer spp. and Fagus grandifolia. Lastly, we show that urban and rural natural parks have similar species diversity within plots, but we found higher variation in community composition among urban natural parks compared to among rural parks. Furthermore, Q. rubra and P. serotina were significantly larger in rural natural parks, indicating that both environmental stress and successional stage could drive compositional differences. Thus, we show that urbanization can have unexpected effects on plant community composition and diversity. Our study refutes the idea that these are degraded habitats, highlights the need to conserve them, and suggests that characterization of local variation in self-assembled urban tree communities will provide the most accurate picture of their management needs and potential ecosystem services.     

How does forest fragmentation affect tree communities? A critical case study in the biodiversity hotspot of New Caledonia

Context

The biodiversity hotspot for conservation of New Caledonia has facing high levels of forest fragmentation. Remnant forests are critical for biodiversity conservation and can help in understanding how does forest fragmentation affect tree communities.

Objective

Determine the effect of habitat configuration and availability on tree communities.

Methods

We mapped forest in a 60 km² landscape and sampled 93 tree communities in 52 forest fragments following stratified random sampling. At each sampling point, we inventoried all trees with a diameter at breast height ≥10 cm within a radius of 10 m. We then analysed the response of the composition, the structure and the richness of tree communities to the fragment size and isolation, distance from the edge, as well as the topographical position.

Results

Our results showed that the distance from the forest edge was the variable that explained the greatest observed variance in tree assemblages. We observed a decrease in the abundance and richness of animal-dispersed trees as well as a decrease in the abundance of large trees with increasing proximity to forest edges. Near forest edges we found a shift in species composition with a dominance of stress-tolerant pioneer species.

Conclusions

Edge-effects are likely to be the main processes that affect remnant forest tree communities after about a century of forest fragmentation. It results in retrogressive successions at the edges leading to a dominance of stress-tolerant species. The vegetation surrounding fragments should be protected to promote the long process of forest extension and subsequently reduce edge-effects.

     

Residential runoff – The role of spatial density and surface cover,with a case study in the Höjeå river catchment,southern Sweden

Depending on the spatial density of built cover and location within a catchment, residential areas make varying contributions to surface runoff throughout different rainfall events. This study examined these contributions and the associated effect of different surface covers and sustainable drainage systems on runoff generation. The Soil Conservation Service curve number (SCS-CN) method was applied to analyse urban development in the Höjeå river catchment in southern Sweden.The results indicated that identical amounts of surface runoff are generated by low-density residential areas on heavy clay soils and high-density residential areas on sandy soils. However, increasing the density of built-up areas on sandy soils is likely to be more disruptive to the hydrological balance and to generate a greatly increasing difference in runoff as building density and impermeable surface area increase. A similar pattern is likely to occur if rainfall intensity increases. It may therefore be appropriate to apply different planning considerations to residential developments depending on the existing soil group, e.g. conserving existing vegetated surfaces on sandy soil and incorporating permeable paving materials and sub-surface infiltration beds in development on clayey soils. Increased area of impermeable surface cover will increase surface runoff in all residential areas, irrespective of building density, soil group and rainfall intensity. However, adapting a systems approach in combining vegetative structures and permeable paving materials with subsurface infiltration beds can help mitigate the impact of surface runoff, particularly in urban developments on clay-rich soils.     

Measuring patterns and mechanism of greenway use – A case from Guangzhou,China

In the context of recent studies that have begun to establish a more quantifiable understanding of the use of urban greenways, this paper presents a preliminary investigation into the patterns in which a greenway is used and the mechanism behind the pattern of use of the greenway. Factors of the location, economic situation, environment and social background have been measured and analyzed in the use intensity model to interpret their impact on the use intensity of different sections of a greenway. The results suggest that use of the Waterfront Greenway in Guangzhou is highly impacted by population density, employment density, nearby service provision and the connectivity of the greenway to other parts of the city. In this case, the use intensity model with indicators such as location, economic, environmental and social factors has been shown to be applicable to the evaluation of the use of the greenways. Results from the case study suggest that providing greenways close to the residential zones, employment centers and key public services such as hospitals and schools will increase greenway use. The surrounding network system of a greenway must be carefully considered and designed to improve the linking of the greenway to other parts of the city, to increase the number of potential visitors to the greenway.     

Are social media data and survey data consistent in measuring park visitation,park satisfaction,and their influencing factors? A case study in Shanghai

Given the importance of urban parks for recreation, it is critical to understand how they are used and perceived. Currently, relatively few studies have examined the public’s activities and preferences at the same time. Social media data are increasingly recognized as a promising data source to study these two aspects. However, little is known regarding the utility and representativeness of social media data for urban parks. In particular, a lack of understanding exists on the comparability of research results measured by bottom-up social media data and top-down official survey data in urban park studies. This research used social media data from Ctrip and Dianping and survey data from the local government agency with park visits statistics and park satisfaction surveys to understand the public’s visitation and satisfaction of 102 urban parks in central Shanghai. We first assessed the similarities between the social media data and survey data by correlation analysis. We then used the negative binomial regression model and beta regression model to examine the matches and mismatches of the different data sources in investigating factors influencing park visitation and park satisfaction. Our correlation results showed that the social media data significantly correlated with the survey data and that social media data performed better in more frequently visited parks. Our regression results showed that the water bodies, recreational facilities, and surrounding commercial facilities were the common influencing factors of park visitation and park satisfaction for all parks. While significant correlations were noticed between these two data sources, we found that the surrounding population density was negatively associated with park visitation measured by social media data but positively associated with park visitation measured by survey data. This study provides a comparative perspective to study park visitation and park satisfaction by combining social media data and official survey data. Clarifying the consistencies and inconsistencies between the social media data and official survey data is important because it could help us to understand the representativeness and potential biases of the social media data when used in visitation monitoring and satisfaction monitoring.     

Linking forest naturalness and human wellbeing—A study on public's experiential connection to remnant forests within a highly urbanized region in Malaysia

Being the country's major economic propellers, Klang Valley region in Malaysia has been experiencing decades of extensive development. Consequently, the lowland dipterocarp forest – which was once the dominant natural ecosystem in this region – has degraded into fragmented remnants, surrounded by urbanized areas. As a degraded natural ecosystem, however, these remnants are still a key ingredient for the city's livability and urban dwellers’ quality of life, by counter-balancing the adverse impacts caused by various urban activities. While these remnants generally fulfilled various physical, mental, and social functions, exposure to different degree of development pressure and human intrusion have caused them to act differently in the way contributing to these functions. This paper presents results of a study conducted in Klang Valley region, with the general goal to contribute to the empirical rationale for linking forest naturalness with human wellbeing. Three remnants, each with different degree of naturalness, were selected as study sites and were hypothesized to contribute to the urban dwellers’ overall wellbeing by enhancing people's physical health, mental health, and social interaction, through fulfilling the motives of visiting the nature. Information on key variables was collected by surveying forest visitors and data were analyzed using path analysis, to depict the causal relationships between forest naturalness and human wellbeing. The study successfully gives the observational support to the potential relation that links together naturalness, experiential connection to nature, and human wellbeing. The study also contributes to the understanding on the meanings of remnant urban nature, which would in turn provide planners a tool to match the urban natural resource management with the needs of the residents.     

High carbon losses from established growing sites delay the carbon sequestration benefits of street tree plantings – A case study in Helsinki,Finland

We assessed the net carbon (C) sequestration dynamics of street tree plantings based on 10 years of measurements at two case study sites each with different tree species in Helsinki, Finland. We assessed C loss from tree soils and tree C accumulation, tested the applicability of pre-existing growth and biomass equations against observations, and estimated the time point for the beginning of net C sequestration for the studied street tree plantings. The tree woody biomass C accumulation in the first 10 years after planting was 18–32 kg per tree. At the same time the C loss from the growth media was at least 170 kg per growth media volume (25 m³) per tree. If this soil C loss was accounted for, the net C sequestration would begin, at best, approximately 30 years after planting. Biomass equations developed for traditional forests predicted more stem biomass and less leaf and branch biomass than measured for the species examined, but total aboveground biomass was generally well predicted.