雅思听力

🎧 Listening Transcript

Today in our environmental science lecture, we'll discuss urban heat islands. Cities are often warmer than surrounding rural areas because concrete and asphalt absorb and retain heat. Trees and green spaces can help mitigate this effect by providing shade and releasing moisture through transpiration. However, the placement of trees is crucial. For example, trees planted on the east and west sides of buildings block low-angle morning and evening sun, reducing cooling costs. In contrast, trees on the south side may block winter sunlight, increasing heating needs. A study in Phoenix showed that strategic tree placement could lower summer temperatures by up to 2 degrees Celsius, but only when combined with reflective roofing materials.