Evergreen trees are plants that retain their leaves throughout the year, unlike deciduous trees that shed their leaves in autumn. Common types of evergreen trees include pine, spruce, and fir. These trees are adapted to various climates and can thrive in both cold and warm environments. The leaves of evergreen trees are often needle-like or scale-like, which helps reduce water loss. This adaptation allows them to survive in areas with harsh weather conditions. Evergreen trees play a vital role in ecosystems, providing habitat for wildlife and contributing to the carbon cycle by absorbing carbon dioxide from the atmosphere.