Replying to my own post: interestingly, the first thing that came to my mind after I posted the beginning of this thread, and was just sitting here thinking about it, was the intro to Halloween 4. Which has always been one of my favorite parts of the whole franchise, by the way. It has all those shots of Halloween preparations and decorations in a rural, agrarian setting, suggesting the possibility of ancient, perhaps pagan beliefs or forces which may somehow have survived in out-of-the-way places, into modern times. So, I have no idea if those scenes were inspired in any way by the Halloween Tree, but it's an intriguing possibility.

It probably has nothing to do with anything. I'm sure Halloween as a "holiday" gave enough inspiration for all sorts of spin-offs. You didn't need to read Ray Bradbury's book to get ideas. Halloween is already oozing with plenty of movie material.

Never read the book, but i liked the Halloween Tree animated film when I was younger. Not sure if it holds up today, but as a kid, it was one of the better Halloween specials out there.

You're probably right... likely, just a coincidence. As a fan of H3 and 4, I would probably find a lot to like about the book, though, so I'm gonna try to track down a a copy. I'm not even sure if I've read it before or not. It sounds very familiar, but I might have just read a Bradbury short story or two with some similar subject matter.