Yes, I know the Creation Kit does not allow to create new actor values. But since I need to create a new Perk Tree I just wanted to know if there is a way to create new Actor Values / Perk Trees externally with another tool.

Not with any free tool. Bethesda holds the (very, very expensive) licenses to several proprietary game dev tools. Those, in combination with whatever homegrown stuff they use, are what handle major game-changers like that.

Sorry.

Guess that plenty of stuff are hardcoded in skyrim.exe to.

You could create your own perk tree, if you're clever about it mate.

If you can make a pic of it, and make it a texture, you could add it to a book in the game. Using a few scripts, some message boxes, maybe a quest or two for aliases, you could easily make a home-grown perk tree for the player.

Other than that the only other way is add your perk tree to an existing tree.

I see. Thanks for your response.