Measuring the Effect of Tree Canopy Cover on Air and Land Surface Temperature during a Heat Wave

Keywords: urban heat island, urban forest, ecosystem services, heat wave
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 09:40 AM (Eastern Time (US & Canada)) - 2/25/2022 11:00 AM (Eastern Time (US & Canada))
Room: Virtual 39

Abstract

The urban heat island effect is an increasing issue as temperatures rise and weather becomes more extreme due to climate change. Extreme heat has health and economic consequences; in the United States 12,000 people die annually during heat waves while there is also a 2 to 4% increase in energy demand for each degree Celsius increase. Research has shown urban trees have an inverse relationship with temperature; however, there is little empirical data and a lack of sampling during heat waves. This research addresses the gaps in the literature by presenting work of the Human-Environment Regional Observatory, a summer research program at Clark University, which monitored air and land surface temperature during two heat waves in July 2021 in Worcester, Massachusetts. 200 site locations along sidewalks were used to measure the cooling impact of trees. 23 species of street trees were surveyed that had diameter at breast height ranging from 2 inches to over 50 inches. Also, surrounding neighborhood tree canopy cover and impervious surface at 10 meter, 30 meter and 90 meter buffers was included in the analysis to control for the surrounding biophysical landscape. Results show that the temperature reduction from street trees was higher during the heat waves than during typical summer days. The tree canopy cover at a 90m buffer explains 44% of the variation in temperature and that for every increase in 6.8% of tree canopy cover, there was a corresponding decrease of 1 degree Fahrenheit.