The team led by Marc Giorgio has really won. With the help of Earth Surveillance methods and powerful laser gauges, they created a perfect model of Vancouver suburbs. They captured every house, tree, and shrub. And then, this "virtual" human settlement was set up against three different scenarios. Street with trees, streets with trees with bare branches and finally streets completely free of vegetation. And to make it a little, these scenarios have added airflow measurements and temperature balances of existing buildings.
"We've found that by removing all the trees, wind speeds in the street can increase up to two times," says Giometto. "While some fifteen kilometers per hour is still a pleasant fresh breeze, the wind speed of 30 km / h is difficult to go, especially if you should go uphill." Trees also play a major role in routing and disturbing wind flow. It is particularly noticeable in cramped passages and narrow vacancies between houses.
"Such a blowout can affect up to a third of energy consumption in a residential building," says Giometto . He counted that removing all trees around the house in his model normally deflects energy consumption for heating by 10% in winter and about 15% energy consumption for air conditioning in the summer. This good service is also done by trees devoid of leaves. "Even the bare branches play a part. Every obstacle takes wind power, so even deciduous trees have their place in the city, " adds Marc Parlange, co-author of the study.
"Similar information provided by our model is required at the level of urban planning. They allow you to predict the effect of storms on buildings, pedestrians and infrastructure. We help create more comfortable cities where trees maximize people's comfort, reduce wind speed and prevent energy losses. "
Trees in megamies? Priceless
The study by Theodore Endreny of the Forestry Faculty of the University of Syracuse, New York, has attempted to quantify the contribution of urban vegetation to current megaměsta (cities with more than 10 million inhabitants). The resulting amount is staggering: approximately $ 482 million will save trees by reducing CO, NO2, SO2, and PM 2.5 and PM 10 emissions. Approximately 11 million will be saved from sewer overload during torrential rains. CO2 sequestration? Eight million. And savings on heating or air conditioning? Half a million dollars.
Author: Radomír Dohnal
Source: Ekolist.cz