Elevation affects bud production OUTDOORS- overall yield is slightly less but resin production is increased. This is because the air is 'thinner' up high, meaning on one hand, CO2 is diminished, but on the other hand, sunlight is a bit more intense. I believe breeders in Switzerland noticed this phenomenon first on their outdoor test crops.

Caveat: This was observed in the ALPS, lol... we don't have much on the East Coast to compare!