Coffee quality is related to altitude. Coffee trees cultivated about 3000 feet above sea level mature more slowly than lower grown trees. The air is drier and thinner, the nights cooler, the soils are younger, the overstory more dense.
The tree has learned that these are less than ideal conditions for seed germination, and every plant is concerned and focused on survival. So to compensate for iffy germination conditions, the tree uses its energy to produce as much food nutrient as it can in one season, for the express purpose of getting it into seeds which are the coffee beans maturing within the fruit (cherry). This food (starches, oils and proteins) provides the seed with the extra energy it will need to germinate under the less than perfect conditions it finds itself in above 3000 feet.
These extra nutrients are what makes specialty coffee taste better than low grown commercial coffees.