The method described, using a wire-screen cone, will work on a bee tree.
It does take a long time, however.  Also, you have to make sure there are
no other passages or entrances into the tree cavity.  If it is an old tree
or partly dead, the bees can often find another way out, or will excavate,
making another entrance, and this will foil your attempt to transfer them
to the nucleus.
 
It is recommended that a comb of brood or two be included in the nucleus,
to provide a colony for the trapped-out bees to enter.  These bees will be
mostly older bees (foragers), so you are mainly transferring old bees, at
least initially, and you can't get ALL of the colony out of the tree.
Given the time and effort, it might be questionable, whether this operation
is worthwhile.
 
After a few weeks there will not be much left of the colony inside the
tree, and you can remove the  nucleus, which will be strong and thriving.
The original colony may build back up, then.  I performed this transfer on
a bee-tree located on a municipal golf course, and the owners were later
disappointed to find the tree-colony bounced back strong as ever.