Summer solstice: Could trees know when it is?

View at EarthSky Community Photos. | Victoria Bryhan captured this beautiful sunrise through the trees on June 5, 2025, a few weeks before the Northern Hemisphere’s summer solstice. Researchers say trees might use the summer solstice as a seasonal marker to trigger shifts in their growth and reproductive cycles.

By Andrew Hacket-Pain, University of Liverpool

The Conversation published this original story on June 19, 2025. Edits by EarthSky.

Do trees know when the summer solstice is?