If you could get some mercaptan like butyl mercaptan, methyl mercaptan or benzothiophene and put it in the stand, nothing within 50 yards will want to be near that stand. All it would take is a small rag and pour about 100 mls on the rag while in the stand and then run. These mercaptans are what is used in natural gas as the odorizer, but this is the pure chemical. Of course I am not sure where you could get some, but since I am a research chemist, I have access to it and have used it before for a similar application. The butyl mercaptan, methyl mercaptan along with sulfuric acid are what skunks spray so you can really make a stink.

You could also put a digital hunting camera in a place where he can't see it and have it facing the stand in a way so you get pictures of him getting into your stand. Then you have evidence and can show him the pictures and tell him you will file charges if he does it again. Or you could just go file charges with the photos. Or maybe you could scare him by getting a local peace officer to contact him and say there is an investigation and have him show the pictures. Then leave it at that.