PTE Academic — Writing

Street trees and city heat

Read the passage below and summarize it using one sentence. Cities are often several degrees warmer than the countryside around them, a pattern known as the urban heat island effect. Dark roofs, roads and car parks absorb sunlight during the day and release it slowly at night, so temperatures in dense neighbourhoods may stay high long after sunset. This matters because prolonged heat is linked to higher rates of hospital admission, particularly among elderly residents and people with heart or lung conditions. One of the cheapest responses available to local councils is to plant more street trees. A mature tree cools its surroundings in two ways: its canopy shades pavements and walls, and water evaporating from its leaves draws heat from the air. Measurements in several cities have found that streets with continuous tree cover can be noticeably cooler at midday than nearby streets without it. However, the benefits are not shared equally. Wealthier suburbs tend to have far more canopy cover than poorer districts, partly because trees were planted there decades ago and partly because residents have the time and influence to campaign for them. Planting is also only the first step: young trees need regular watering for several years, and many die before they provide meaningful shade. Researchers therefore argue that councils should direct new planting to the hottest and least-shaded neighbourhoods first, and should budget for long-term care rather than counting only the number of saplings put in the ground.

• Identify the main idea of the whole passage.
• Include the key supporting points and leave out minor detail.
• Write one complete sentence, in your own words where you can.