system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do evergreens not shed their needles like other trees shed leaves?
gpt
They actually do, but the needles last from 2-7 years instead of just one. The tree is always "green" because needles drop at different times. It's an evolved trait. Based on their design, evergreens can get enough energy from sunlight year round to support keeping their leaves (the needles are technically leaves) attached and functioning.

Edit: Also evergreens can handle snow better do to their cone-like shape. Broad leaf trees will lose a lot of branches in an early winter storm because their leaves allow them to collect much more weight, but the branches cannot support it.

And as some users said below, water conservation plays a role.