Look at the twigs. Maple twigs have the little branches directly across from each other where as oaks and others are staggered. The only other tree (I believe) that has the branches directly across from one another is the Ash and it's very easy to tell them apart. With that being said, it's not always easy to see the twigs when they are way up high.
1st year - 6 taps and a turkey fryer and 1 gallon of syrup
2nd year - 12 taps, turkey fryer and another gallon of syrup
3rd year - 45 taps, new propane setup and 5 gallons of syrup