[gowld]

> It is not the case that these oaks were kept for the express purpose of replacing the Hall ceiling.

> The oaks, however, are left to grow on and eventally, after 150 years or more, they yield large pieces for major construction work such as beams, knees etc.

Splitting hairs a bit. In fact what they did was to maintain a more general solution, maintaining a supply of wood over the long term of 400 years.