Why do pine trees stay green in winter?
Show answer & explanation
Answer: Needles have waxy coating
Produce antifreeze chemicals — Wrong. Though pines do have some antifreeze-like compounds, the main reason they keep needles is their waxy coating and small surface area reduce water loss dramatically compared to broad leaves.
Continue photosynthesis slowly — Wrong. While evergreens can photosynthesize slowly in winter, they keep green needles primarily because waxy coating and small size prevent water loss, making it efficient to retain them year-round.
Needles have waxy coating ✓ — Correct! Pine needles have thick waxy coating and small surface area, which minimizes water loss through transpiration. This makes it efficient to keep them year-round rather than regrow annually. Needle shape, waxy cuticle, and sunken stomata all reduce water loss. In harsh climates where growing season is short, keeping needles saves energy. That's why they're 'evergreen'!