In all urban climate change adaptation strategies, an increased use of vegetation in cities is asked for. The reason for this demand is the known positive climate effect, as it is true for big parks and street trees as an example. In city planning there is therefore a demand for as many and as large as possible areas for tree plantings and als public, green open spaces. In Bavarian agglomerations this demand however is oposed by a vast population growth, so that green areas are threatened by redensification and highly sealed contruction types. Moreover, because of undergrund technical infrastructures such as cables, subways, underground parking areas it is in several urban situations hardly possible to plant trees and provide adequate rooting ground respectively, for a longterm healty development of these trees. A possible solution is the use of trees in containers. These are recently used more and more in public and are discussed in architecture as an option for intensive greening of structures. Trees in containters though are characterized by an extremely limited rooting area, which reduces also the development of the tree crown. Moreover the trees and especially the roots are exposed to extreme, often critical growth conditions such as high temperature variations, strong frost and water deficits, what effects growth and provided ecosystem services. The urban climatic effects by shading and evapotranspiration are therefore different to assess than for free growing trees in normal soils.
This research project aims to close existng knowlegde gaps in relation to the climatic effect and growth conditions of trees in containers to plant future trees in containers properly and use then sustainable as urban climatic effective measures. Therefore the objectives of the project are:
- Which requirements in terms of vegetation and technic must be fulfilled that trees can longterm develop well in containers and fulfill demands in terms of microclimate and design?
- Which technics (sort of container, substrate, watering technic) and tree species are suitable for different site conditions?
Growth and Ecosystem Services
- How can the microclimatic effects of trees in containers be recorded and modelled?
- Which differences regarding growth and ecosystem services of the studied tree species can be found depending on single variables (sort of container, substrate, watering technic)?
Design and Implementation
- Which aesthetic spatial impact and sojourn quality do open areas and green architecturals provide, which can be designed and implemented based on the developed methodic and technical basis?
- How can they be linked synergetic and aesthetic with other measures of climate change adaptation (e.g. rainwater management/flood protection, grey water recycling) to aim for greatest sustainability and resilience for cities?
The results will be summarized in a guideline which allows Bavarian cities and municipalities to use trees in containers purposefully and sustainable as a measure for the adapation to climate change and increase of biodiversity in dense urban situations when conventional plantings are not possible.