Right or Wrong?

The family behind me consists of a mother and several children, the youngest of whom is a boy about 13 or 14 years old. I'm not sure how many of the kids currently live with the mom, but this boy seems to be pretty full-time right now.

The kid picked up a new hobby this year. It's axe-throwing. I don't know why he's doing it, but he is. He throws the axe at a large fir tree in their backyard. By large, think over 2 feet in diameter, and correspondingly tall, much like the tree in my backyard. Our yards are about 7500 square feet, btw. At first Axel was not that good at axe-throwing, so the axe tended to bounce off the tree. With months of practice, he's improved a lot, and the tree is showing visible wear and tear to its bark. I can see some of the damage from my backdoor, about 100 feet from the tree, and I can't see the side he most often uses as a target. I think it's probably in worse shape. Mom seems oblivious to Axel's throwing.

Today Axel was in his yard with a couple of buddies. He was goofing around with the axe, doing amusing (?) things like chopping hard at the (much smaller) tree supporting the hammock where his friends were lying. He also jokingly (?) threatened his friends with his axe. Mom is still oblivious.

I'm a non-confrontational chickenshit, but with 2 car accidents in one year, I'm getting a little paranoid about irritating my insurance company. I think they would be annoyed if that stupid tree fell in my direction, even though it (like my car accidents) was not my fault. I, too, would be annoyed. A fall in my direction would do many nasty things including taking out electricity, phone, and cable lines for everyone north of us. The tree would probably hit my house and damage it. It also could hit MY big fir which would fall on at least my garage and car (parked in front of the garage, while the fir is behind the garage) and probably would also hit the Good Neighbors' house and/or their big firs setting off another round of fir tree crashes onto houses. Like I said, I'm a paranoid, non-confrontational chickenshit. And I'm one who doesn't want to find out how the insurance companies would allot blame for this, because I'm certain there will be more blame than money. I can't afford to be out of my house for months while the damage is fixed, either. My nearest sibling is 2000 miles away, so commuting from there is not reasonable, either.

In my passive-aggressive way, I looked up the owner of the property behind me, using the county property records (sidenote: it's kind of creepy how much info they display about one's house there) on the internet. As I thought, Axel's mom rents. So I called the real property owner and told them that the kid was using an axe on the tree and damaging it.

Right thing to do? Wrong? I think it would've been nicer or fairer or something to talk to Axel's mom directly, but I was loathe to do that. She's often home when he's axe-throwing, so how could she not know about it? If she knows about it and doesn't stop it, to me that implies she sees nothing wrong with the behavior. Do I have the right to tell her the behavior is wrong and she needs to stop it? It's a value judgment I'm not comfortable saying to her face, although I'll tell the world via blog that I think it's wrong and she needs to stop it. What's up with this? It's not like we've been close friends ever since I moved in. We rarely speak and those instances have usually been dog-related like the time her kids were teasing my dogs through the fence. I did confront directly over that one to stop it immediately.

How does one become less of a paranoid, conflict-avoidant, trying-to-appear-nonjudgmental-when-I-really-am chickenshit? Suggestions welcome!