It's implied in the Wiki:
Foraging is the skill associated with gathering wild resources found on the ground throughout Stardew Valley, and with chopping down Trees. Foraging skill also increases by harvesting crops grown from Wild Seeds.
stardewvalleywiki.com
that Forage spawn and their locations are randomly chosen, however with all the posts here about similar game "RNG" from
@BlaDe and others,
I don't know if that's a random event based on a pre-randomized value derived from the Seed, or if it's randomized on the fly, either daily or weekly.
Based on many other things in the game, I'd bet it's actually Seed-based so hopefully someone has a great Foraging seed for you!
That said, I believe Fishing and getting the Tea Sapling recipe from Caroline at 2
will likely give you a higher return on investment than just Forage. Unless of course you're using that Forage for the Tea Sapling recipe at which point, kudos to you!