Interesting way to make a lamp to display or show the wood, Came out nice.
I was wondering: in order to help reduce the epoxy foaming as you show, and to also reduce the amount of epoxy required while making this process a little easier, have you considered inserting a hollow tube in the middle of the mold?
This eliminates the drilling requirement & reduces both the amount of epoxy & wood needed. I'm also thinking that this would help with aligning the wood sticks around the lamp base in a vertical mannerĀ so a greater volume of wood is exposed on the surface of the base.
The tube could be made by rolling some cardboard, like the thick back of a paper tablet, and could be adjusted for any size diameter desired.
That's all, just rambling while thinking. Nice lamp.