The green world and waste

Tree roots hold the soil, leaves catch dust from the air and clean it, and trees give shade and coolness. Rain washes the leaves, so they can catch dust again. Where trees are few, fertile land slowly turns to sand and dust storms grow more frequent. This process is called desertification. To stop it, plants that grow in the desert, such as saxaul saplings, are planted. In cities too, greening streets and house walls makes the air cooler. When planting saplings, work together with a specialist and adults.