Was it purchased or did you grow from seed? And where are you located? Only two species are native to the US and are pretty much endemic to two specific areas. And the entire genus is not very active in commerce as well.

It was grown from a seed by a friend. Seeds gathered from a park tree in Italy, so... a long way from any natural Torreya stand. They are hard to come across here in Europe too. Maybe this might be useful, it overwintered in this pot totally unprotected except some mulch on the ground and we had quite harsh winter (-15C / 5F for several nights, maybe even colder with cold winds, heavy snow etc.). And as can be seen the tree got out like there's no winter at all. I don't know how cold hardy US Torreya's are but this one is obviously quite strong. If it is US Torreya of course.

Thanks

Maybe T. nucifera? I think this species is more hardy than T. grandis.

Was it collected at Villa Taranto on Lago Maggiore in North Italy?

Hi.

No, I believe it was collected in Udine or somewhere close by. North eastern end of Italy close to the border of Slovenia.

Torreya californica.

Note that tops of plants are hardier than roots with old interior roots being hardier than the outer layer of new roots so without looking at the roots you don't know if there was no damage yet. Frozen camellia plants can remain green until flowering time and then drop everything, demonstrate that they are in fact dead.