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 for maximum cooling effect is not the total area but the density of trees. For example, a small park with mature, closely planted trees can be more effective than a large, open grassy field. Also, the placement matters: green spaces should be evenly distributed, especially near residential areas, to provide accessible cooling. Interestingly, water features, like ponds, add humidity, which can sometimes worsen the heat in dry climates, so they are less recommended than tree canopies.