Hi Arturo,
We are indeed blessed with so much natural beauty, especially the trees! I Googled Bariloche, Rio Negro, Argentina, and am amazed at your location so far away from Buenos Aries. You are nearer the Pacific Ocean than the Atlantic. And I am impressed that you are in the foot hills of the Andes Mountains! There is great natural beauty all about you, especially the mountains. (And I add you are almost in Chile.)
Sassafras here is very plentiful. However it would be impossible to send seeds or plant material with the strict customs laws of most nations. It is a very difficult thing to do here or internationally. However, birds carry and plant the seeds naturally throughout the region, and it is not uncommon to find seeds germinating naturally within the gardens and flower beds. I am sending you this link at ATP which you might have already seen.
Sassafras (Sassafras albidum)
Have not had experience with Tupelo or Black gum, Nyssa Sylvatica. We have locally a 'Sweet Gum', but I do not have them.
American Sweetgum (Liquidambar styraciflua)
Best Wishes, Leon
