A cork tree made of other materials?
I don't see any reason why a cork tree couldn't be created using other materials.  Wooden dowels, cut in one inch sections could be hot melt glued together for a similar effect.  The same could be done with cross sections cut from small tree branches.

On a larger scale, you could assemble a similar tree from empty aluminum cans or water bottles.  In both of those cases, you would want to align the containers upside down relative to the front of the artwork so that decorations can be added to their comparatively featureless bottom sides.

Theoretically, you could scale this up to paint cans, barrels or any grouping of cylindrical objects.