IMHO, I would NEVER just leave a note in the mailbox. If a person did that to me there is no way I would call them. I want a person that wants to meet me face to face, and I want to size him up for his level of intelligence (or lack of common sense) and his level of respect for me etc. If a guy leaves a note in the box that shows me that he doesn't have the time in his day to meet me, and sit down for a while and talk; he doesn't want to face me unless he knows for sure that he is going to get something out of the deal.
I found my first 2 years supply of wood by knocking on the door a mile down the road from my house. But the thing that I found for a lifetime was a friend. Older, retired guy. I knocked on the door, his wife answered, he was shortly behind. I asked about the wood and he said, "Come on in, take a seat." We talked for a while, he explained that he "had rules" when it comes to cutting wood. There were some other people cutting at his place too, and he didn't want anybody to get upset. He explained the rules, most notably, #1 you have to take some of the poplar if you're going to take the ash, oak, or maple. #2, if you cut it, you can take it, but don't touch any wood that was cut by anybody else. #3 ask about any trees in question
I followed all of the those rules, and he was an extremely friendly helpful guy. I asked about the hickory tree, he said that he was cutting on that one for his own wood so please leave it. I cut up a poplar first, then a white ash. I went to pick up the load of white ash the next night, it was later, and he didn't realize I had picked it up. The next day he asked me about it, because he didn't know I had come and got it, and he just wanted to make sure that nobody else took it. He was serious about his rules, (he didn't want me to get screwed on the wood that I had already bucked).
Anyways, I got down further into the woods where the path was partially blocked off, he offered to pull the tree tops out of the way with his tractor. Then he asked me how I was splitting my wood. I said by hand, and he sent his hydraulic splitter home with me that night. When I brought the splitter back, his wife sent a pie home with me.
I just saw him in town the other day and asked how he was doing. We talked for a while, then he mentioned another oak he was going to take down. Said he'd pull it up into the edge of the yard with the tractor so I could get to it easily, then it's all mine.
Extremely nice couple, and I'm glad that I knocked on the door rather than left a note in the box etc.
Always knock on the door, meet the person, and make a friend. BTW, treat the person and their property with absolute respect, when in doubt, ask permission etc before doing something. Never do anything that the property owner says not to do, and make sure that they're satisfied.
