From Alan James – 9 October 2020
Aye, I should have thought of Kingussie, it’s phonetically possible (cf. our recent discussion of [i]/[ɪ] pronunciations of Cuil, Buittle etc.), though as you say the only reflex of giuthsach we seem to have in Galloway is -goosie. Maxwell opined that referred to relics of pines found in the peat-bogs, but if present–day palaeobotanists are right about the age of those fossils and the extent of the retreat of P. sylvestris, while I don’t underestimate the old Gaelic speakers, I’m a bit doubtful whether they’d have identified them with trees they’d only have seen – if at all- a long way to the north. I wonder if giu(th)as had come to be used of another conifer, viz. juniper, the only one that would have been growing in the region. Come to think of it, I don’t recall coming across aitean in Galloway p-ns?
Still, the wood appears on the 1854 map as fairly open scrubby ground dotted with conifers. If you’re right, either Gaelic was still current when those were planted, which I doubt would have been before 1700, or pines clung on a lot later than the palaeobotanists tell us.