I had no idea it took that long for those things to grow. My wife's family is in a northern part of Ohio where maple sugar is an industry. I know I've seen the things planted in rows, so those must have been planted decades ago.
I've got red oaks and Burr oaks in my nature preserve that are 3-4ft caliper trees and are probably less than 100 years old. Much fast growing than maples, apparently.

Aren't you a little squeamish about tapping a 400 year old tree??