Why do leaves turn red in the fall?
The dazzling array of colours produced by many trees each autumn is one of nature’s most beautiful displays. But while we know that warm, sunny days combined with cool nights produce the most vivid colours, scientists don’t really know why tree leaves change colour – particularly red.
They do, however, have two strong theories.
Biologist Susan Dudley spends an entire lecture on the subject each year. She explains the “Sunscreen Hypothesis” and the “Honest Signal Hypothesis” below.
Why exactly do leaves turn red in the fall, anyway? Biologist Susan Dudley explains. #science pic.twitter.com/JLrzkyJR7q
— McMaster University (@McMasterU) October 22, 2015
