Lehtierin

Lehtierin is a term of Finnish origin that translates to "leaf separation" or "leaf fall." It refers to the natural process by which deciduous trees and shrubs shed their leaves, typically in autumn. This phenomenon is a crucial adaptation for plants in temperate and colder climates, allowing them to conserve water and energy during the winter months when sunlight is scarce and temperatures are low.

The process of lehtierin is triggered by changes in environmental conditions, primarily the decrease in daylight hours and cooler temperatures. As these changes occur, trees begin to produce a layer of cells called the abscission layer at the base of the leaf stalk. This layer gradually weakens the connection between the leaf and the stem. Simultaneously, the chlorophyll, the pigment responsible for the green color of leaves, breaks down, revealing other pigments such as carotenoids (yellows and oranges) and anthocyanins (reds and purples), which were present but masked by the chlorophyll.

Once the abscission layer is sufficiently formed, the leaf detaches from the tree, falling to the ground. The fallen leaves then decompose, returning nutrients to the soil, which can be used by the tree or other plants in the ecosystem. Lehtierin is a visually striking natural event, often associated with the vibrant colors of autumn foliage, and it plays a significant role in the ecological cycles of many regions.