Fastest way to train Herblore?

That's okay, don't worry about it. You have to manually gather the wood with 5 members accounts to clear the amount of wood that you need if you want to unlock the avatar.

(Nothing like kingdom )

Gathering the wood is similar to ivy, only it doesn't last as long; semi afkable. It's quite a lot of work for a single person to run 5 accounts for the first week, but after the inital build tick (first week), you only have to gather with 1 character + make the avatar gather for you.

Unfortunately, you won't have access to the avatar during the first week to gather for you.

 

Prayer pots Duh !