Leaves still on trees

[k9]

Hi folks, I know I should know this, but, why do some of the younger trees esp the beech keep their brown leaves through the winter but the older ones usually all fall, is it something to do with the sap?
k9

[ron1863]

Leaves don't drop off the majority of trees, they are pushed off.
On very close examination where a leaf has been pushed off the branch, you will see a fine layer of cork like substance called an abscission layer, as it forms it gradually pushes the leaf off the branch.
The Beech tree is unique in that this abscission layer does not form and the leaves are left hanging on the tree until Spring when the new bud growth pushes the old leaf off the tree.

[k9]

Thanks for that, great info k9

[ron1863]

Only too glad to help K9