Salem

When seeking to find things like Giant Willow Aphids, what counts as Foraging?

Picking things up off the ground that haven't been picked up before.

What about Picking Leaves/Branches or Chopping Wood or Harvesting Bark?

Just wanting to maximize my chances.

I havent managed to get any rare foragable, or 2x loot from interactions with trees, so my guess is nope.
Just pick things up from the ground that would have spawned there naturally, such as flowers, grass, rotten logs, shrooms etc.

Reaper6971 wrote:When seeking to find things like Giant Willow Aphids, what counts as Foraging?

The context is important.
Some items that are found "when foraging" other things are found when you 'pick' things.
Others are found on the ground as their own individual type.
Others are only found inside decay-clock spawning containers such as hollow logs and tree stumps.

For aphids, pick up every rotton lock and pick every piece of grass in the biome.
For singing logs - look inside hollow logs and stumps in the red parts of Autumnal biomes.
For torn tentacles, pick every reed on the beach.
A new world gourd will be laying on the ground by itself.

I'm trying to find out where to look for a Steer Skull myself - I've emptied the nearby deserts for days and not found one yet.

Steer Skull just lies on the floor. Same as Singing Old Log (if You are lucky You can find some old logs in stump/logs [same as lime with purity] because they didn't despawn from there after rework)

Steer skulls- I have found two in my time. They have been found on the ground themselves showing up on the minimap and not inside anything or a bonus when foraging.