Today, in our environmental science lecture, we're going to discuss the impact of urban green spaces on city temperatures. A recent study conducted in Melbourne compared two areas: one with dense tree coverage and another with mostly concrete surfaces. The results showed that during a heatwave, the tree-covered area was up to 4 degrees Celsius cooler than the concrete area. Interestingly, the cooling effect was strongest in the late afternoon, not at midday as many might expect. This is because trees release moisture through transpiration, which peaks later in the day when the sun's angle changes. The study suggests that increasing tree canopy by just 30% could significantly reduce the urban heat island effect, but it requires careful planning to avoid blocking wind flow.