Approximation
Bite a tree's root with your fang to get an approximation on its age. It won't be exact, this isn't scientific or anything, but it will be pretty close.
Once you have an approximation on the age, you'll be able to come up with an approximation on how much it's worth too.
がい
おおむ
None
As you're recording your approximation down, somebody comes up and shouts, “Hey guy (がい)! I’ll give you $10,000 for that tree there, guy!” This guy must be crazy. That’s much more than your approximation of the value of this thing. But you sell it to the guy anyway.
The guy is trying to look at your approximation now, while calling YOU "guy" over and over, and you just want him to buy it and leave you alone!