Here's why:
* Abscission Layer: This specialized layer of cells forms at the base of the petiole (leaf stalk) in deciduous trees. It weakens the connection between the leaf and the stem, allowing the leaf to detach cleanly during autumn.
* Deciduous Trees: These trees lose their leaves seasonally, typically in autumn or winter.
* Evergreen Trees: These trees retain their leaves year-round, constantly replacing older leaves with new ones.
Without an abscission layer, a tree wouldn't be able to shed its leaves in a controlled manner. Therefore, such a tree would likely be evergreen, even if it were genetically programmed to be deciduous.
It's important to remember that there are some exceptions. Some evergreen trees do have abscission layers, but they use them to shed leaves at different times of the year or under specific environmental conditions.
