After an exhaustive search, this is the only FM antenna I could find currently for sale. It's working well for me. Your trees shouldn't be an issue.
MCM also sells rotors and other antenna mounting accessories. Their customer service is excellent.
Looks like a nice product and very affordable!
I have explored yogiboy's recommendation about the Rescue Electronics LP-8 (U.S.A.), and have been in contact with Paul the manufacturer. This looks like one seriously rugged design with good looking specs. And, Paul has provided me with some quality information. Where I live, we have these Chinook winds, that can gust over 100mph. This antenna is pricey, however. I'm going to continue to explore the LP-8. There are also a number of directional antennas still being made in Great Britain, but they're pricey and especially pricey to ship.