The characters standing with spirit(s) of the woods need to be decent—good as well. Running rampant, chopping trees, killing game, and not giving anything back (sacrificing fresh meat cuts or cooked meals).
As
@PALU mentioned, it’s speculation to a point*, but whenever I play a character that might go killing lone old men, stealing stuff from villages and being generally a not-nice type: the guest either doesn’t trigger, or might take to year+ ingame. When a nice type, with daily sacrifices seem to trigger “forest spirit” quest within 3 ingame months.
*anything not verified by the Enormous Elks is mostly speculation. Especially thing related to spirits. Sami has emphasized on several occasions that the spirit dealings should remain mysterious.