In the False Bride / I loved a lass (lad) / Week before Easter family of songs, some versions include the verse:

The men in yon forest, they all ask of me
How many strawberries grow in the salt sea?
I ask them the same, I ask them quite plain
How many ships sail in the forest?

The verse doesn't really add anything to the narrative, and seems to have 'wandered in' from another song, presumably one of the large range of 'impossible riddle' types.

However, I've not heard the verse used except in the song family mentioned.

Any ideas?

Jim