During the 1930s, Raymond Stadleman (then working as an "Agricultural Explorer" for the USDA) collected tobacco seed of a Havana-type tobacco cultivated on the upper slopes of Huana Picchu (adjacent to Machu Picchu). Stadelman described it as having a distinct, "white blossom". I have grown out that seed here in southwest Virginia. It produces a lovely Havana-type leaf, similar to Vuelta Abajo leaf, but displays rich, pink blossoms. [Since it had no actual name--only a number assigned by ARS-GRIN, I named it "Machu Picchu Havana".]
While hiking the crest of Roan Mountain in North Carolina, I discovered a fat, thornless blackberry. I considered taking a root of it home. Another hiker said that he had done that some years earlier, and that once it was growing at a lower altitude, it always produced thorns.
So altitude affects a number of plant traits. How does it affect tobacco flavor/aroma? That is difficult to assess. Some of the nicest cigar leaf grown in Ecuador is grown at or near the cloud forests--high altitude, but nearly constant humidity and cloud. I believe the Peruvian cigar leaf that WLT sells is a variety similar to Machu Picchu. My Machu Picchu has a "warmer" more "rounded" aroma, when compared to the "Peru" leaf, which seems to have a less complex flavor profile. Is that altitude? Is that cultural practices? Is that differences in curing conditions? I don't know.
My general impression is that period of direct sun exposure, average growing temperature and soil fertility/hydration, as well as curing conditions, are the primary determinants of what kind of finished tobacco you get.
Bob