Lots of problems with fungus attacks and pests caused the loss of several secondary branches that needs to be re-grown. The photo is from November of 96, the tree still suffers from the fungus that during two subsequent years caused the first flush of leaves to blacken and fall off.
Fortunately, Oaks are very hardy and are used to pest and fungus attacks, also in nature they have to set a second set of leaves, but it does weaken the plant.

I think I have succeeded in treating the fungus and I now plan to pinch the top but otherwise let the tree grow freely to recover its strength.