Weather Explainers

Weather Words: Leaf Marcescence

Leaf marcescence is when trees hold onto their dry leaves through winter, protecting buds and enriching the soil come spring.

Some trees hold onto their leaves long after most others have dropped them. Have you ever wondered what keeps these leaves clinging in the depths of winter?

It’s a phenomenon known as leaf marcescence. While most deciduous trees shed their foliage in autumn, certain species, like oaks and beeches, often keep their dry, brown leaves through the winter months. These marcescent leaves can make trees look as if they’re still clinging to autumn, even when the snow starts to fall.

Scientists aren’t completely certain why some trees display leaf marcescence, but several theories have emerged. One idea is that holding onto leaves may protect the tree’s buds from harsh winter winds or deter browsing by deer and other herbivores.

Another theory suggests that when these leaves eventually fall in spring, they help enrich the soil around the tree, acting as a natural mulch and providing nutrients at a critical time of growth.

For nature lovers and weather watchers alike, leaf marcescence is more than just a visual curiosity. It serves as a reminder of how trees have adapted to seasonal changes in clever ways. Observing which trees retain their leaves can even provide clues about local climate patterns, wind exposure, and the resilience of different species in winter weather.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.