His license restriction won't work in the United States. He says "USA has already been excluded from using Treefinder in February 2015," but his exclusion is ineffective in the United States. You can download his work without agreeing to any license, and under United States law, once you lawfully possess a copy of a protected work, you need neither a license nor permission to use it. 17 USC 106 lists the things you do need a license or permission to do, such as preparing derivative works or distributing copies. Mere use is absolutely not covered.
And it would be somewhat silly if it worked any other way. Say you bought a book at the bookstore. Do you still need a license to read it? If so, where is that license? What are its terms?
Under United States law, one who lawfully possesses a protected work is entitled to the ordinary use of that work.