Any of youins ever use a metal detector like this on residential trees? I am thinking of trying to sell some logs in the future and, not only would it come in handy for that, I am thinking it would help save some saw chains, and my mind from frustration 
http://www.ebay.com/soc/itm/121041642728;jsessionid=D3A62F0C46C3DB537D93C2A4BFB9FF70

http://www.ebay.com/soc/itm/121041642728;jsessionid=D3A62F0C46C3DB537D93C2A4BFB9FF70