What causes some trees to hold onto their leaves well into Winter?
This occurrence is called Marcescence. While Marcescence is a normal occurrence for Beech trees it also occasionally occurs in different varieties of Oak, Pear, and Ironwood on a more frequent basis.
Early cold and frost can create this leaf retention occurrence on a variety of other trees and shrubs as well. No one has ever been able to figure out what a tree’s purpose for doing this is. Experts seem to agree however that this does not indicate any particular stress or weakness within the tree.
If you notice trees doing this, their leaves may finally sporadically disengage from the tree throughout the Winter. Many leaves will remain on the tree all Winter long and into the Spring and not fall until a new flush of fresh growth ‘unglues’ them and pushes them from the tree. This will create extra Spring cleanup.