How do you dry out leaves that don't normally dry naturally?

Why some leaves dont fall off?

• There is a tree outside my window that still has it's leaves. I mean it's not just a few leaves, but the majority of them are still on. They are brown and dead and the tree was alive in the fall and did what trees normally do. Why is this?

• Answer:

  Some trees, like oak, beech and cottoneaster shrubs, do not shed their dead leaves until spring. 1. This may protect low branches from foraging deer. The withered, tannin bitter, non-nutritious leaves may deter deer from feeding on the tasty live twigs and buds during the winter's lean months. 2. Another thought is the leaves are frost protection in winter. Just as gardeners wrap tender plants to shield them from sudden freeze thaw cycles so the tree wraps itself in a still air layer. 3. Retaining the leaves over the winter may allow the tree a longer window of nutrient retrieval from the dying leaves. If the retrieval can take a bit longer in fall, since the leaf drop does not have to be completed til spring, a bit more sugar can be taken into winter storage for spring regrowth. This may tie to another selective factor.... 4. Holding the leaves until spring offers a nice late egg-laying site in the fall season. This offers a shelter other locations lack so attracts the insects that lay eggs to overwinter just to drop the butterfly larvae with the old leaves before they hatch, and before the new leaf buds open.