Summer has come to an end, the school year is starting again, it’s getting colder and we have to start putting on our heavier jackets. But if there is one moment that tells us the seasons are really changing, it’s the falling of the leaves. But, why do they fall?
Firstly, we have to know that there are two types of leaves, perennial leaves that stay intact all year (pine needles for example), and deciduous, leaves which start to change color, dry up and fall from trees at a certain time of year. But why does this happen?
Leaves get their energy from the sun and provide trees with the nutrients they need to survive; in the fall, since there is less light, they can’t complete their mission. They start to change color, turning shades of orange, brown and yellow. Water is another essential element for leaves, it helps them to complete the photosynthesis process; but when it gets cold, leaves run the risk of freezing and dying, preventing other leaves from taking their place.
What does the tree do to avoid this? It generates a series of cells between the leaf’s stem and the tree branch which makes leaves fall. When the weather warms up again and there is more light, leaves grow back so that they can carry out their vital task.