I have been pulling my hair out trying to find "Crumpled Leaf" for these new swords. I finally gave in and googled it. I know, I know. Now, this is not too much of a spoiler, since it is pretty much invaluable to know for any of the higher level crafting IMO. So, Here
is a link to a page explaining where you can find the various resources.
Basically, if anyone finds an area in the level range 13-20 WITH trees, please let me know so I can get these swords going.
I had a good explore of the island today and the highest outdoor level range I could find was 10... so I may need to go further afield.