Oak Tree

Just a quickie today after yesterday's exhausting day.
I found out that there's an oak tree growing in our back yard! It's already about 1m tall. The oak tree is not so common tree in Finland anymore, due to the colder climate and it grows in a quite narrow part of Southern Finland. I think it's a beautiful tree, and hopefully it'll keep growing at our back yard and producing more oak babies ;)

Does anyone know what these balls are under the leaf, are they some sort of insect or a tree disease?


Helsinki Blippers, please notice the Pikkujoulu Blipmeet at 29.10.!