Each coffee tree produces very few beans that can be harvested. Also, the coffee tree can only be found in very tropical climates which mean that it can only be found in countries close to the equator. That being said, the coffee tree grows in more than 70 different countries.
The word 'beans' is deliberately in single-quote marks, since the thing that gets roasted and ground to make the drink isn't really a bean at all, it's a seed.
There are usually 2 seeds inside each fruit. That is the case with most types of this tree with the exception of the peaberry. The seeds are surrounded by a somewhat slimy white substance which is the meat of the fruit. All this from a tree that can grow to between 20 and 50 feet tall.
For a coffee tree to really grow, thrive and produce well requires warm temperatures, 60F to 70F, and water. The tree will produce better in an area that gets frequent rains. That is why the countries closest to the equator line are ideal.
High altitudes of course means less oxygen in the air and this is also a condition in which the coffee tree thrives. The steamy air that is produced by the hot climates and rainy most weather put these trees in the sauna like condition that they love and thrive in.
The robusta, or coffea canephora, goes into making the majority of coffee because it can be grown at lower altitudes and is more disease resistant. But it's the high-altitude coffea arabica that forms the base of a gourmet cup.
Some fruit trees thrive on intense sun. Coffee trees do not fall in this category. Providing shade and shelter for them helps protect the trees from windy conditions and filters the suns rays allowing the tree to grow and produce at its best.
The process from reaping from your tree is a long one. From its beginning to the point where the tree will produce fruit is a period of about 5 years. Once it begins to produce you will only get about 2 pounds of coffee from each tree.
There is nothing easy or mindless about the harvesting of coffee beans. Everything is done by hand and it takes a keen eye and knowledge of what you're doing to separate the good beans from the bad. From one tree you can harvest about 2000 beans, and it is a tedious task.