Young oak in a pot

lindgren_zoe

Three years ago when both my in-laws sadly passed away, I planted an oak in a container for the family, intending to eventually place it where their ashes are scattered. Last autumn, I potted it up into a larger container. It has been doing well overall, but this year it only developed leaves below the leader. The leader itself looks fine with buds on, but they did not develop into leaves. Can anyone kindly explain why this has happened?

Fairygirl

Oaks become huge, so unless you intend bonsai-ing it, or root pruning it, you won't be able to keep it thriving long term in a container. Unless you own the ground where you eventually want to plant it, you'll need permission for that too. 
It's quite likely, considering the conditions in many areas this year [and previous years] that it's very thirsty, and can't support the buds farthest away from the water source. 

Shrubs/trees - plants in general - will use various methods to preserve themselves in drought. Shedding foliage early for example. Not fully developing flower or foliage buds is another. 
They can't survive in just compost either - they need a soil based medium. Compost just dries out and disappears. 

Silver surfer

Oak trees have deep tap roots.
Kept in a pot the roots will go round in circles.
They strangle the main stem and strangle the tree.
Planted out are never happy.
Leading to eventually wind rock and toppling.

lindgren_zoe

Thank you so very much for your time and input Fairly Girl and Silver surfer - much appreciated. 
It all makes sense now. The top leaves did not develop because it was too dry at the base! The reason I repotted it at three years old was to check that roots were not girdling/forming circles and all was well, (amazing pics Silver surfer).
The oak's intended final location is on private land where there is plenty of space for it to thrive and hopefully become a significant tree one day. 

Loxley

It might make sense to grow it on in a temporary spot in the ground rather than in a pot. On nurseries they undercut the roots to encourage a fibrous root system and make it easier to transplant, you could achieve the same by digging up and replanting during the winter.

Dovefromabove

This may be of interest

http://www.deepdale-trees.co.uk/trees/air-pot-system.html

bertrand-mabel

We were given an oak that had been in a pot for many years and we planted it in our garden. It took a long time to say thank you for the release but is now a very healthy young tree.