Today in our environmental science lecture, we're discussing urban green spaces. A recent study in Melbourne found that increasing tree canopy cover by just 10% could reduce city temperatures by up to 2 degrees Celsius during summer heatwaves. However, the researchers noted that this effect is only significant when trees are planted in clusters, not isolated along streets. Additionally, they highlighted that parks with native species require less water than those with exotic plants, making them more sustainable in drought-prone areas. The study also emphasized that community involvement in planting initiatives greatly improves long-term maintenance success.
❓ According to the lecture, what condition is necessary for trees to effectively reduce city temperatures?
A. A. Trees must be planted in large numbers along every street.
B. B. Trees should be grouped together in clusters.
C. C. Only native tree species can provide cooling effects.
D. D. Community members must water the trees regularly.