Sustainable Landscape Architecture

In the context of expected climate change, urban and landscape planning faces particular challenges. The buffering of heat waves and the handling of severe rain events are the key challenges that are currently being pursued in the context of adapting strategies to climate change. One of the core tools for mitigating negative climate change effects is the use of green infrastructure, in which an increase in urban trees is a key function.

However, plants in general and urban trees in particular are  often exposed to hostile conditions in built-up areas. These include, on the one hand, general location conditions such as inadequate space for root systems or soil compaction, and on the other hand extreme climatic conditions caused by the urban structure.

In the urban wind field, acceleration effects can occur due to jet effects and zones of increased turbulence, which can lead to multiple wind loads compared to average conditions. Conversely, often in the immediate vicinity of such strong wind regions, there are zones with very low wind speeds and stagnating air masses. Here, the physical impulses for the city trees are small, but plant and animal pests can develop, which can also lead to damage to the tree substance and thus to the physical stability.

In order to understand the contribution of individual buildings to the urban microclimate system, and to assess the energy exchange between the interior of the building and the outside microclimate, all elements must be simulated in an integrated simulation framework. The holistic and high-resolution approach of ENVI_MET allows for the simulation of the microscale urban metabolism as a complex system and the energy fluxes at the individual façade element of a single building.

ENVI_MET Tree Pass

Finding the optimal growing conditions for selected plants or supporting landscape architects in finding the optimal planting scheme: The ENVI_MET Tree Pass is a comprehensive summary of all relevant microclimate growing conditions.

In the context of the ENVI_MET_Tree Pass method, plants or trees take on a central importance. For example, wind loads, water consumption and growing conditions at different sites can be investigated and compared to the plants‘ needs. The analysis of (potential) tree sites with regard to the local wind conditions in relation to the tree size and geometry is an important instrument for adapted landscape planning as well as preventive disaster protection.

The high-resolution micro-climate model represents the tree crown in general as a three-dimensional point cloud of different leaf surface densities connected to a stem skeleton. This approach allows a first quantitative assessment of the hazard potential caused by wind loads depending on tree geometry, location and meteorological situation. In addition to the purely physical forces that affect the tree‘s stability during strong wind events, the longer-term conditions of the site are of great importance. If strong wind events are accompanied with unusual wind directions, trees that are normally wind protected and therefore untrained may be more susceptible to damage.

The simulation can also be used to extend the risk assessment for trees to other relevant aspects such as pest infestation, thermal stress and water stress. The latter aspect is already used today in simulations for climate adaptation of cities.