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.