After all of the wind, rain and snow we have seen this fall, how can there still be leaves clinging to the branches of some oak trees? Most of them are brown and look dead, but why hasn't the tree yet shed these leaves?
Marcescence is the retention of dead plant organs that are normally shed. It is used most often to refer to persistent leaves, but can also be used when discussing other parts of a plant, such as flower corollas. Leaf marcescence is most often seen on juvenile plants and may disappear as a tree matures. This is the case with the American beech tree, whose pale tan leaves often persist all winter long on young trees.
Some species of trees, such as many varieties of the mighty oak, are notably marcescent. They retain all or some of their dead leaves in winter no matter their age, only shedding their old leaves in the spring once new leaves begin to bud.