hahah. Congrats! I'm very happy that it worked out for you and I was able to help in the end :)
Good luck with the rest of the challenges. Let me know when you've completed the last one and are one step ahead of me. Then you can help me :P

I DID IT! THANK YOU SO MUCH! You rock! I owe you one!

Really? Oh my God. I really can't pick them from the trees. I'll try here. If it works I owe you one. I also want to 100% the game, but this challenge broke me.

Oh yes, I remember that. But that was quite a long time ago. If I'm not mistaken, you just have to cut down the trees that you know from your experience have vines. Then they suddenly lie on the ground like dropped items. You can't "pick" them from the tree and they never started to show up for me.

I'm in the second challenge, there's a bug where the "vines" don't appear on the trees. Did you have this problem?

Yes, unfortunately. I've done 6 of the 7 challenges and tried the last one 2-3 times. Unfortunately, I was a few minutes too slow on my last attempt and then I didn't feel like doing it anymore, because you have to invest so much time in the last challenge and when you realize a few minutes before the end that you can't do it, you've really wasted a lot of time for nothing. I will certainly try it again at some point. I also don't want to start the DLC before I have all the achievements in the main game.