Do I have to consume the lonely fruit from the "Lonely Tree" expansion during the year I get it, or can I store it in the settlement storage and consume it, when I feel "ready"?
Same for any other Ressource, that can be used for some benefits (like shimmering mane or vermin).
I know you can't bring it to a future hunt, but can you use it later?
I haven't yet played the lonely tree expansion in a campaign, so I'm not including anything about those rules.
Expansion-specific rules aside, you never have to consume anything unless directed to consume. Even the binge-eating disorder doesn't force you to immediately consume something when you acquire it...however, given the option to consume or not you must always attempt to consume with that disorder.
Other items like shimmering mane etc may be recorded and archived per the normal rules at the end of the settlement phase. They may be used in a subsequent settlement phase as if you held the card in your hand including the ability to archive the card for a special benefit.
Note that fresh acanthus is a resource, though, and may NOT be brought back out on a hunt once it reaches the settlement for the first time. Only dried acanthus may be brought from a settlement phase to a hunt as it has a gear grid card.