Papers by Stephan Pauleit
Springer eBooks, 2021
Sensitivity to external disturbances such as floods, heat waves, summer droughts, tsunamis or hur... more Sensitivity to external disturbances such as floods, heat waves, summer droughts, tsunamis or hurricanes is very high in sensitive urban ecosystems. Urban ecosystems are generally vulnerable due to their open material cycles. In particular, the chapter provides insights which effects the foreseeable climate change will have on cities and how they can be counteracted. In addition, it will be shown which problems urban ecosystems in particular are exposed to under the aspect of global change and which concepts are conceivable for a reduction of vulnerability. Special attention is paid to the development of urban resilience. Urban structure, city size and urban region will be given special attention with case studies.
HAL (Le Centre pour la Communication Scientifique Directe), 2014
An important driving force behind urban expansion is the growth of the urban population. But for ... more An important driving force behind urban expansion is the growth of the urban population. But for Europe, this is not a sufficient explanation. The major trend is that European cities have become much less compact. Since the mid-1950s European cities have expanded on average by 78%, whereas the population has grown by only 33%. In the PLUREL project-an integrated project within the EU's 6th Research Framework Programme-more than 100 researchers from 15 countries analysed the impacts of urban land consumption at a pan-European level and, through six European and one Chinese case studies, identified how land use conflicts and the pressure towards periurban areas can be strategically managed in different development and regulatory contexts. To summarise, the following strategies were identified as important steps towards more sustainable urban-rural futures: (i) better coordination of transport, land use and open space planning; (ii) urban containment and densificationdevelopment of a green compact city; (iii) preservation of blue and green infrastructure; and (iv) preservation of agricultural land and the promotion of local production. The need also remains to strengthen governance at the regional level while at the pan-European level there is clearly a need for more policy attention to be given to urban-rural linkages.
Sustainability, 2019
Under changing climatic conditions, drought may become a critical constraint for trees in urban a... more Under changing climatic conditions, drought may become a critical constraint for trees in urban areas, particularly at roadsides and highly paved squares. As healthy urban trees have proven to be an important mitigation and adaptation tool for climate change as well as a significant provider of ecosystem services, there is a need for planting species and cultivars capable of coping with the limited water supply. However, data on species' and cultivars' response to drought, particularly their water supplying root systems remains rare. To consider the whole plant responses to drought situations, we studied the growth and phenology of three frequently planted tree species and cultivars with a diameter of 5-6 cm during a one-year rainfall exclusion experiment conducted in a nursery field as well as the dry biomass of the compartments branch, stem, and root after excavation. Our results revealed that species' and cultivars' performance were linked to their within-plant carbon partitioning. A high tolerance to drought was noted for Acer campestre, with a particularly high ratio of root:shoot ratio, which made it presumably less susceptible to droughts. Tilia cordata 'Greenspire' was highly affected by the reduced water availability visible through prematurely leaf senescence, while Carpinus betulus 'Fastigiata' suffered from losing a considerable part of its root biomass, which resulted in the lowest root:shoot ratio of all species and cultivars. This study demonstrated the need for investigating the reaction patterns of species and cultivars by considering both the above-and the below-ground plant parts. We recommend that, for future tree plantings at harsh and challenging urban sites, an important selection criterion should be species' and cultivars' capability to develop and retain strong and dense root systems even under limited water supply, as that is believed to be an important trait for drought tolerance.
International Journal of Biometeorology, Oct 18, 2020
Extremely high temperatures, which negatively affect the human health and plant performances, are... more Extremely high temperatures, which negatively affect the human health and plant performances, are becoming more frequent in cities. Urban green infrastructure, particularly trees, can mitigate this issue through cooling due to transpiration, and shading. Temperature regulation by trees depends on feedbacks among the climate, water supply, and plant physiology. However, in contrast to forest or general ecosystem models, most current urban tree models still lack basic processes, such as the consideration of soil water limitation, or have not been evaluated sufficiently. In this study, we present a new model that couples the soil water balance with energy calculations to assess the physiological responses and microclimate effects of a common urban street-tree species (Tilia cordata Mill.) on temperature regulation. We contrast two urban sites in Munich, Germany, with different degree of surface sealing at which microclimate and transpiration had been measured. Simulations indicate that differences in wind speed and soil water supply can be made responsible for the differences in transpiration. Nevertheless, the calculation of the overall energy balance showed that the shading effect, which depends on the leaf area index and canopy cover, contributes the most to the temperature reduction at midday. Finally, we demonstrate that the consideration of soil water availability for stomatal conductance has realistic impacts on the calculation of gaseous pollutant uptake (e.g., ozone). In conclusion, the presented model has demonstrated its ability to quantify two major ecosystem services (temperature mitigation and air pollution removal) consistently in dependence on meteorological and site conditions.
Gaia (Heidelberg), Mar 27, 2014
Cab Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, Oct 12, 2011
Urban areas are particularly susceptible to climate change. For instance, effects of increasing t... more Urban areas are particularly susceptible to climate change. For instance, effects of increasing temperatures on public health and energy demands for cooling of buildings are further intensified by the urban heat island effect, and the current sewer infrastructure is not designed to handle predicted rainstorm events. Urban green spaces can play a role in climate change mitigation approaches, but in particular with regard to climate change adaptation . This includes moderation of urban temperatures as well as linking green spaces and stormwater management. However, climate change also influences the growth conditions of urban vegetation, and as beneficial effects depend on vital and lush plants, establishment and management practices of urban plantings have to adapt to climate change challenges as well. While environmental, social and economic benefits of urban green space are well established, there is still a significant lack of knowledge for the site adapted planning and design of a green infrastructure in a given location to meet the challenges of climate change.
<p>Urban green and blue spaces such as water bodies, parks and street trees reduce outdoor ... more <p>Urban green and blue spaces such as water bodies, parks and street trees reduce outdoor temperatures and energy consumption of buildings through evaporative cooling and shading and are thus promoted as nature based solutions to enhance climate resilience. However, in growing cities, supply of urban green space often conflicts with increasing housing demand, resulting in dense neighbourhoods with lack of green. Therefore, the transdisciplinary project &#8220;Future green city&#8221; seeks to identify possibilities for balancing population growth and increasing living space demand with the development of nature-based solutions for climate change adaptation. In a transdisciplinary approach with the City of Munich, living labs are used to investigate how nature-based solutions can be integrated into spatial planning processes.</p><p>For the case of an urban redevelopment site with row buildings and a vast amount of greenery, eight densification scenarios were elaborated with city planners to derive planning guidelines for the further development of the area. The scenarios consider the effects of densification with additional floors and new buildings, the use of new building materials and energy efficiency standards, the construction of underground car parks and consequently a loss of green space to varying degrees. We are particularly interested in the interplay of densification and availability of green and its impact on indoor and outdoor thermal comfort, energy efficiency of buildings and their life cycle based emission balance. Microclimate modelling is employed to quantify and evaluate the impacts of densification on outdoor thermal conditions during heat days and the benefits of urban green in reducing heat stress.</p><p>First modelling results show that additional floors have less impact on human thermal comfort than loss of green space caused by the provision of required parking space. Though underground car parking avoids surface soil sealing, it leads to the removal of existing urban green and excludes the planting of large trees. Informal instruments such as mobility concepts can reduce space consumption by car parking. Moreover, urban redevelopment also bears the potential to increase climate resilience of the stock by targeted greening strategies. The potential is greater, the earlier climate change adaptation is considered as a topic in planning processes. Modelling helps to explore strength and weaknesses of different alternatives in early design stages.</p>
Zenodo (CERN European Organization for Nuclear Research), Mar 27, 2014
An important driving force behind urban expansion is the growth of the urban population. But for ... more An important driving force behind urban expansion is the growth of the urban population. But for Europe, this is not a sufficient explanation. The major trend is that European cities have become much less compact. Since the mid-1950s European cities have expanded on average by 78%, whereas the population has grown by only 33%. In the PLUREL project-an integrated project within the EU's 6th Research Framework Programme-more than 100 researchers from 15 countries analysed the impacts of urban land consumption at a pan-European level and, through six European and one Chinese case studies, identified how land use conflicts and the pressure towards periurban areas can be strategically managed in different development and regulatory contexts. To summarise, the following strategies were identified as important steps towards more sustainable urban-rural futures: (i) better coordination of transport, land use and open space planning; (ii) urban containment and densificationdevelopment of a green compact city; (iii) preservation of blue and green infrastructure; and (iv) preservation of agricultural land and the promotion of local production. The need also remains to strengthen governance at the regional level while at the pan-European level there is clearly a need for more policy attention to be given to urban-rural linkages.
Forests
Urban forests play a critical role in improving the quality of life in cities, but in arid enviro... more Urban forests play a critical role in improving the quality of life in cities, but in arid environments, little is known about the potential benefits and growth conditions of different tree species. Our study aimed to fill this gap by investigating the relationships between tree dimensions, above-ground biomass carbon storage, and shading potential in three common urban trees in the arid city of Jericho, Palestine, (i.e., Ficus nitida, Delonix regia, and Phoenix dactylifera). The trees were chosen according to their distribution in urban locations and tree vitality, with ages ranging from 20 to 90 years. Based on the results from tree structure measurements, the carbon storage and shading potential were calculated using the City Tree model. The results indicate a moderate to strong relationship between tree height, crown diameter, and crown volume for F. nitida and D. regia (R2 = 0.28–0.66), but no relationship for P. dactylifera (R2 = 0.03–0.06). The findings suggest that the analy...
Land
Urban spaces are often dominated by paved surfaces and ongoing processes of densification; conseq... more Urban spaces are often dominated by paved surfaces and ongoing processes of densification; consequently, intensifying the urban heat island effect. In order to strengthen the liveability of urban spaces, an adequate amount of green spaces is needed. Trees in planters are an alternative greening solution; however, the lack of root space due to underground infrastructure poses a challenge. Furthermore, temporal aspects such as tree growth, tree death, and growth responses to environmental factors are frequently overlooked in projects that use trees in planters. In multiple case studies that employ the method “Research through Drawing” we analyse five selected projects, which deal in sharply contrasting ways with the temporal aspects of trees in planters. Our results show that promising approaches exist, albeit they are not described explicitly in either written or graphical form. Consequently, temporal aspects are only vaguely considered in the projects’ design concept. This results i...
Forests
With the increasing individualization of society, perceptions and attitudes towards nature and fo... more With the increasing individualization of society, perceptions and attitudes towards nature and forest management is changing. Knowledge about motives for visiting woodlands as well as the aesthetic perception of forests can support forest management and communication strategies. In Central Europe, multifunctional, close-to-nature silviculture aims to convert the still dominating conifer monocultures towards mixed, structured forests to establish forests that are better adapted to the changing climate, thus enhancing the value for nature conservation and increasing their ability to provide ecosystem services. Reflecting these management objectives, we examined the perception and scenic preferences of the resulting forest stands in Munich´s urban proximate woodlands. We applied both surveys with choice experiments using visualizations of different forest stands and conducted Photovoice walks. In the choice experiments, most interviewees preferred the visualizations of mixed forests. D...
HAL (Le Centre pour la Communication Scientifique Directe), Sep 26, 2016
National audienc
Planning for Climate Change, 2018
Urban Forestry & Urban Greening, 2021
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Papers by Stephan Pauleit