I had a challenge last summer when one of my hives swarmed and alighted
on a tree branch about 25 ft high, and a good 6-7' out from the trunk
of the (Hemlock) tree. As a new-bee, this was my first experience
capturing a swarm so my adrenalin was flowing!
 
I was able to get my extension ladder up to the
level of the branch, after cutting some branches away.  I attached
the handle of a 5 gallon plastic bucket to an aluminum pole. Standing
on the ladder, I and was able to position the bucket below the swarm;
when I lifted it up into the swarm, I caught about 50% of the swarm. The ones I
missed returned to cluster on the same branch.
 
I must have gotten the queen on the first try, as they basically stayed
in the bucket as I climbed down the ladder with it.
 
It took four of these operations until I had gotten 90% of the swarm.
 
About one week later, I noticed there was still an apple sized ball of
bees on that same branch. I went back up and got them too!
 
All in all, it was quite an experience for a first timer!
 
Roland