I very respectfully disagree with Northwest PA Beekeeper and txbeek. You can put a trap on the bee tree and using the Hogan method, you can take multiple swarms each year ( 2 to 4) and still leave the bees where they are. Swarm traps are hit and miss at best,(more often miss) where taking swarms using a trap is virtually a sure thing on a tree, tank, or anywhere you can place the transition close to the feral brood nest.
In this type of trap, your trap becomes an integral part of the feral colony, and the trap is just another place for the queen to lay eggs. In taking swarms you don't install the funnel, and allow the queen to come into the trap to lay. Then you remove the frames containing her eggs and move the frames, allowing the bees to make a queen from her eggs. In early Spring, during a good honey flow you can take the queen and let the feral colony make themselves a new queen, then trap again.
This does involve some visits to the trap, but, the chances are far better for getting genetics than just placing swarm traps around the area. If some distance is involved the cost of gas may be a factor.
If I had 3 trees nearby I would trap. I could turn that into 9 to 20 swarms each year.
cchoganjr