Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that adding more trees to city streets can reduce local temperatures by up to 2 degrees Celsius during summer. This happens because trees provide shade and release water vapor through their leaves, a process called transpiration. However, the study also noted that the effect is strongest when trees are planted in clusters rather than isolated. For example, a single tree near a busy road had little impact, but a line of trees along a park boundary created a noticeable cooling zone. So, city planners should prioritize planting groups of trees in heat-prone areas.
❓ According to the lecture, what condition makes urban trees most effective at reducing temperature?
A. A. Planting trees along busy roads
B. B. Planting trees in clusters or groups
C. C. Planting trees near park boundaries only
D. D. Planting isolated trees in various locations