ISA Certified Arborist Practice Exam

What is one effect of insufficient tree canopy cover in urban areas?

1. Better air circulation

2. Increased heat stress

3. Higher soil moisture

4. Improved aesthetics

The correct answer is: Increased heat stress

Insufficient tree canopy cover in urban areas leads to increased heat stress primarily due to the loss of shade and the urban heat island effect. Trees play a crucial role in moderating temperatures by providing shade and through the process of transpiration, where trees release moisture into the air, thereby cooling the surrounding environment. Without adequate tree cover, surfaces such as asphalt and concrete absorb and radiate heat, leading to higher temperatures. In urban settings with limited greenery, the combination of heat absorption and lack of cooling relief from trees results in elevated temperatures, which can intensify heat stress among residents and wildlife, increase energy demands for cooling, and exacerbate overall environmental stressors. This effect underscores the importance of maintaining tree cover to promote cooler, more sustainable urban spaces.