Đề thi VSTEP Reading B2 — Vai trò làm mát của cây xanh đô thị

As global temperatures rise, cities are searching for ways to stay cool. One surprisingly effective solution may be as simple as a tree. Researchers studying the urban heat island effect — where concrete absorbs and radiates heat — have found that a mature tree equals running two air conditioners for a day. Trees cool cities in two ways. Their canopies block sunlight, lowering surface temperatures on roads and buildings. Through evapotranspiration, leaves also release water vapor that cools the surrounding air. A single oak can transpire up to 380 liters of water on a hot summer day. Cities are taking notice. Singapore has pledged to plant one million more trees by 2030. Medellín, Colombia, has built "green corridors" along its rivers to connect fragmented parks, reducing heat while improving air quality. However, expanding urban forests is not without challenges. Mature trees need decades to grow, and maintenance requires ongoing funding. As climate change accelerates, planners must balance immediate cooling technology with long-term natural solutions.