Today, in our environmental science lecture, we'll discuss 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 instance, trees planted along streets provide more cooling effect than those clustered in a single large park. Additionally, green roofs on buildings help manage rainwater runoff, but they require regular maintenance. Interestingly, even small pocket parks, if evenly distributed, can improve air quality significantly. So, when planning sustainable cities, we must prioritize connectivity and accessibility of green areas over sheer size.