Puuduvahetust

Puuduvahetust refers to the process of changing or replacing a tree's leaves. This is a natural biological phenomenon that occurs in most deciduous plants, and some evergreen species also undergo a form of leaf shedding. The primary reason for puuduvahetust is to adapt to environmental changes, particularly seasonal shifts in temperature and light availability.

In deciduous trees, puuduvahetust is a strategy to conserve water and energy during the colder months or dry seasons. As temperatures drop and sunlight diminishes, the leaves become less efficient at photosynthesis. The tree then begins to break down the chlorophyll, the green pigment responsible for capturing light, revealing other pigments like carotenoids (yellows and oranges) and anthocyanins (reds and purples). This process often leads to the vibrant fall colors observed in many regions. Eventually, a layer of cells called the abscission layer forms at the base of the leaf stalk, weakening it until the leaf detaches and falls.

Evergreen trees, while retaining their leaves year-round, also experience a gradual replacement. Individual leaves on an evergreen tree have a lifespan, and as they age and become less effective, they are shed and replaced by new growth. This process is typically less noticeable than the mass shedding of deciduous trees. Puuduvahetust is a vital part of the plant life cycle, contributing to nutrient cycling in ecosystems as fallen leaves decompose and enrich the soil.