Thomas B. Randrup

Health promoting outdoor environments - Associations between green space, and health, health-related quality of life and stress based on a Danish national representative survey

Aims: To investigate the associations between green space and health, health-related quality of life and stress, respectively. Methods: Data were derived from the 2005 Danish Health Interview Survey and are based on a region-stratified random sample of 21,832 adults. Data were collected via face-to-face interviews followed by a self-administered questionnaire, including the SF-36, which measures eight dimensions of health and the Perceived Stress Scale, which measures self-reported stress. A total of 11,238 respondents completed the interview and returned the questionnaire. Multiple logistic regression analyses were performed to investigate the association between distance to green space and self-perceived stress. Results: Danes living more than 1 km away from the nearest green space report poorer health and health-related quality of life, i.e. lower mean scores on all eight SF-36 dimensions of health than respondents living closer. Respondents living more than 1 km away from a green space have 1.42 higher odds of experiencing stress than do respondents living less than 300 m from a green space. Respondents not reporting stress are more likely to visit a green space than are respondents reporting stress. Reasons for visiting green spaces differ significantly depending on whether or not respondents experience stress. Respondents reporting stress are likely to use green spaces to reduce stress. Conclusions: An association between distance to a green space and health and health-related quality of life was found. Further, the results indicate awareness among Danes that green spaces may be of importance in managing stress and that green spaces may play an important role as health-promoting environments.

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

Abstract 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.

Selection of trees for urban forestry in the Nordic countries

Abstract Trees in the urban environment are subjected to a number of stresses which are very different from those suffered by trees in typical rural conditions. The stresses listed in this paper should be a basis for the selection criteria used in urban tree improvement programs. The basic properties of trees are climatic adaptation, disease resistance and a large phenotypic plasticity. Properties related to the urban situation are related to stresses caused by social factors, the restrictive soil volume and crown space, soil pollution, air pollution, de-icing salt, wind and drought. In addition, aesthetic factors, growth form and growth potential and resistance to breakage of limbs are important selection criteria. The priority ranking of the selection criteria depends on the environment wherein the plants are to be used. The need to broaden the range of species and cultivars planted in Nordic cities should have high priority, and selection programs should, therefore, include new species of urban trees. A practical selection should be made within the four major Nordic climatic regions, which are the northern maritime, northern continental, southern maritime and southern continental regions. The establishment of broad co-operation in the selection of plant materials for urban uses is discussed.

Towards an understanding of udeskole: education outside the classroom in a Danish context

In the past decade, an increasing number of Danish public, private and independent schools have introduced regular compulsory education outside the classroom for children aged 7–16 as a weekly or biweekly ‘outdoor school’ day – known in Danish as udeskole. An analysis of this form of outdoor education, its impacts and provision has been undertaken. Findings suggest that udeskole can add value to normal classroom teaching especially with regards to health, social and well-being perspectives. Future recommendations include collaborative strategies between researchers, local government sectors, and educational and landscape planners and managers to improve the impact and provision of udeskole in the Danish school system. Further, it is important to understand this grassroots movement of devoted teachers from both an educational and green management perspective.

A review of tree root conflicts with sidewalks, curbs, and roads

Literature relevant to tree root and urban infrastructure conflicts is reviewed. Although tree roots can conflict with many infrastructure elements, sidewalk and curb conflicts are the focus of this review. Construction protocols, urban soils, root growth, and causal factors (soil conditions, limited planting space, tree size, variation in root architecture, management practices, and construction materials) are discussed. Because costs related to sidewalk and curb damage are substantial, a review of research addressing repair, mitigation, prevention, and litigation costs is included. Finally, future research needs are discussed.Potential for conflicts between trees and sidewalks/curbs is high when one or more of these factors are present: tree species that are large at maturity, fast growing trees, trees planted in restricted soil volumes, shallow top soil (hard-pan underneath top-soil), shallow foundations underneath the sidewalk (limited or no base materials), shallow irrigation, distances between the tree and sidewalk of less than 2.0–3.0 m., trees greater than 15 to 20 years old.The results of this survey indicate that cities are spending substantial sums of money to address conflicts between street tree roots and infrastructure. It can be inferred that most of these expenditures are spent dealing with problems that already exist. However, this raises the question: How much is being spent now to ensure that conflicts are minimized in the future?Future research should concentrate on plant factors, site design, and construction of sidewalks and curbs. Also, more knowledge is needed about interactions between root growth and management techniques, such as pruning and irrigation. Finally, there is need for studies that will assist policy-makers to efficiently allocate funds among repair, mitigation, prevention, and legal remedies.

The Abiotic Urban Environment: Impact of Urban Growing Conditions on Urban Vegetation

‘Planting of trees in towns should not be given in senseless and untrained hands, because one has to fight against unfavorable soil-, airand other conditions. From noticing them the safe and prospering development of expensive establishments highly depends’ (translated from Fintelmann 1877). Depending on the geographic situation and the urban structure, the environmental conditions in urbanized areas are more or less harsh and they differ from natural growing conditions. The impact of the urban environment on urban vegetation is neither constant in intensity nor periodical. There are numerous constraints that are crucial for the survival and vitality of urban vegetation. This chapter focuses on basic abiotic growing conditions in urbanized areas, on artificial deviations from the natural undisturbed habitat quality in forests that contribute to stresses and threats for urban vegetation. This includes both the qualitative and quantitative impact of different site factors and the time-scale as well: specifics of urban climate, air pollution, constraints and peculiarities of urban hydrological cycles, urban soil conditions in general and in particular unfavorable physical soil properties, unbalanced nutrient supply, soil pollution and fire problems. Possible remedies and precautions to improve growing conditions for urban trees are implicated. In short, the interactions between human activities and the urban environment are discussed to help minimize abiotic stresses that reduce the vigor and vitality especially of trees, and that increase their susceptibility to biotic stresses. Vice versa the impact of urban vegetation on urban ecology is summarized.

The Concept of Urban Forestry in Europe

This book provides a comprehensive perspective on the status of urban forestry with a primary focus on Europe. Before addressing various aspects of urban forestry, the applied terminology and definitions should be discussed. This is especially of relevance as the concepts of urban forests and urban forestry are relatively new and subjects of ongoing debate. The chapter examines the concept of urban forestry from three related aspects. It starts with a general introduction about the use of concepts, definitions and terms in natural resource management and forestry. It then briefly summarizes the development of the urban forestry concept, as well as its definition in a North American context. Next, the implementation and use of the concept in Europe is discussed. As the concept and definition of urban forestry still evoke debate, especially regarding their delimitation from other related terms, the chapter ends with proposing a possible framework for a European definition of urban forestry.

Influence of planning and design on soil compaction in construction sites

Abstract The influence of planning and design on soil compaction was analysed at 17 construction sites randomly selected in the suburbs of Copenhagen, Denmark. Soil compaction was estimated by bulk densities, and sampling sites were located inside and outside construction areas. Bulk densities were taken at the soil surface and down to a depth of 1.0 m at 0.1 -m intervals. Organising and planning inputs at construction sites were assessed by studying work specifications, supported by subsequent interviews. On the basis of this classification, it was determined whether or not planning and design had an influence on soil compaction in planting areas. Unexpectedly, no significant differences regarding soil compaction were found between types of contracting, whether landscape architects were involved or not, or between different qualities of work specifications. The absence of differences is believed to be caused by unintended soil compaction, which is a result of construction site traffic occurring on areas not meant for traffic, i.e., areas meant for planting. To prevent unintended soil compaction, it is suggested that the entire construction area be divided into zones. Zoning will control the construction traffic patterns more efficiently. Landscape planning, design and specifications should be carried out with respect to these zones.

Occurrence of tree roots in Danish municipal sewer systems.

Summary The occurrence of tree roots in Danish municipal sewer systems was studied via a survey sent to all Danish cities. It consisted of 28 questions focusing on the following three areas; 1. statistical information on the municipal sewer systems, 2. degree of root intrusion into sewer systems, and 3. municipal planning procedures in relation to root intrusions in sewer systems. In general, Danish cities do not perceive root intrusion as a major problem. Root intrusion occurred in both main and combined pipes, but was most severe in service connection pipes. Typically, the problem occurred within 6 metres of a tree. The problem is believed to be especially common in residential areas, with species of willow (Salix, sp.), poplar (Populus sp.) and Birch (Betula sp.) reported as the most commonly troublesome. Root intrusion primarily occurred in pipe systems laid before 1979 but can also occur in post-1979 systems. Problems in newer systems are most common in concrete pipes and in joints between two pipes. Closed circuit television inspection (CCTV) is used as a preventative tool and in emergency situations of root intrusions. Roots were removed from an average of approximately 1.1-km (± 1.4 km) of piping/year/city. Costs were separated into two different categories: 1) costs related to root removal and 2) costs associated with pipe replacement/renewal due to roots. In total, the annual expense per capita was

Nature-Based Solutions and Climate Change – Four Shades of Green

1.73. Based on small, medium, and large cities (< 16.000 inhabitants, 16.000- 50.000, and > 50.000 inhabitants, respectively), the costs per capita tended to be higher in medium-sized cities (