There us a huge difference between an Oak in a forest setting,sheltered by other trees, and one that has been set aside as a single , memorial tree.
The old oaks in England, and here for that matter, grew up as part fo a forest canopy and stayed that way.
The ones here survived because the terrain made logging impossible back in 1806 when the English stole our naval fleet and the whole country started growing oaks, so we could build a new one and get revenge.
Took about...............hold your breath..........................1500 mature oaks to build a frigate, before they were iron-clad.
By the times the "Naval oaks" were mature, ships were buillt of iron.