As the global climate increases, how will Venice feel in the future? Cool Forest explores themes of urban heat, adaptation, and biodiversity. The forest pavilion exhibits vegetation that is adapted to Venice’s future climate, and sensors monitor and visualize its cooling effects, as well as the response of trees extreme heat and drought. Cool Forest reinforces the links between the vegetal world and street temperatures to spark dialogue about global cities and landscape as infrastructure for urban climate adaptation.
As a window into Venice’s future climate, Cool Forest is an interactive journey through a lush, planted microenvironment. As visitors walk along the promenade, they learn about the biodiversity of the forest, engage with urban cooling methods, and consider our climate-changed future. The plants are future visitors, foreshadowing the species that will eventually join the current ecosystem as the climate of Venice shifts. By highlighting a cluster of these future biotic regions, the species selection in Cool Forest also sparks conversation about assisted adaptation of existing regional ecosystems as a component crucial to climate-resilient landscapes.
Embedded sensors track the growth and change of plant species within the installation, while other sensors track microclimate conditions within, and surrounding the installation. Collectively, the installation presents a digital repository of heat data, harnessing the power of technology to understand our changing climate.
Cities are hot and getting hotter. When compared to nearby rural areas, cities may be anywhere from 1-5 C warmer. This urban heat island phenomenon is a result of the hardscape that dominates the city. These surfaces absorb and retain heat, slowly radiating it back into the urban air.
As global temperatures rise, so will the urgency to mitigate the urban heat effect. Cities in northern Italy are projected to experience summer temperature increases up to 7C by 2080. A recent study of ‘city analogues’ estimates that by the end of the century, Venice’s climate will be like today’s conditions in Riyad.
Cool Forest is an exploration of urban microclimate and how cities can design with trees to beat the heat. The intervention relies on a dense planting plan that promotes competition and mimics what would naturally happen in native forests.
Trees reduce air temperature through shade and transpiration. Shaded surfaces are estimated to be 11-25 C cooler than peak temperatures of unshaded surfaces and materials. Trees also cool the air through transpiration, a process through which they release water vapor into the atmosphere. This process lowers air temperatures, cooling the tree, as well as reducing peak summer temperatures by 1-5 C.
A network of sensors distributed throughout Cool Forest visualizes the microclimate. Air temperature, humidity, and the heat index (what the temperature feels like to the human body) are displayed in real-time. (insert Sensor Diagram)
Just like people, trees are impacted by warming climates. Some will adapt, some will not. Transpiration not only contributes to the cooling performance of trees, but it also signals how a tree is handling the heat. Transpiration occurs when sun and water are available. Under heat stress, trees may increase transpiration to regulate temperature. However, excessive heat can lead to water loss and stomatal closure, reducing transpiration. This balance reflects a tree's adaptation to manage heat stress.
Transpiration can be measured by the rate that sap moves up and down within a tree. The faster the sap moves up, the greater the rate of transpiration. Cool Forest uses special sensors called thermal dissipation probes to measure sap flow rates. In Cool Forest, the sensor lights depict the direction (up and down) as well as the rate of sap flow movement (cm/hr) in the tree. A sensor moving quickly vertically is transpiring at a high rate and actively cooling the surrounding environment. Little or no observed sap movement during daytime conditions indicates tree stress.