Persistent Dead Leaves on Winter Trees

 By Richard Primack 

 

“The death scenes of great men are agreeable to consider only when they make another and harmonious chapter of their lives.” Henry David Thoreau in Early Essays and Miscellanies.

 

Many trees retain dead leaves on their branches during cold winter months, in a phenomenon known as leaf marcescence (LM). Theses leaves typically fall off during the late winter or early spring.  

Photo 1: White oak tree with marcescent leaves.

 

Photo 2: Close up of persistent white oak leaves.

Many theories have been advanced to explain LM. For example, persistent leaves may protect the buds against grazing by animals or give the growing plants a burst of mineral nutrients when they fall to the ground and decay in spring. But none of these have been proven so far. 

Photo 3: American beech shows LM on its lower branches. 

There has never been a systematic survey of the plant kingdom to determine the extent of LM. To remedy this, in 2024, an international network of 18 botanical gardens will investigate the occurrence of LM in their collections using a standard protocol. 

Photo 4: Surveying LM at the Arnold Arboretum.

Some plants show persisting green leaves that fall off in the winter, and these species are being included in the survey. 

Photo 5: Persistent drooping green leaves of Viburnum veitchii.

A recent article reviewed theories regarding the advantages of LM: LINK