Today, in our environmental science lecture, we're discussing urban green spaces. Recent studies show that parks and community gardens can reduce city temperatures by up to 5 degrees Celsius. However, the key factor isn't just the number of trees, but their placement. For example, trees planted along streets provide more cooling than those clustered in a single park, because they shade surfaces where heat accumulates. Additionally, green roofs are effective but costly to install. Interestingly, a small park with varied plant species attracts more wildlife than a larger one with uniform grass. So, when designing sustainable cities, planners must prioritize strategic tree positioning over total green area.