I'm speaking for myself now, not "management," but I think plant trading is discouraged. There are lots of laws/ regulations about what can be shipped where, which ordinary people are probably not aware of. But they are there for a reason, to try to prevent more pests from being spread around. Most often insect pests and plant diseases appear in a region carried along with plants that are shipped there.
Look for your sumac in local nurseries or reputable catalogs that are aware of the regulations and know how to do clean packing.