Why Are Haiti's Coffee Trees So Tall?

Why Are Haiti's Coffee Trees So Tall? - Reason.com:
"...In Haiti, coffee grows on trees.
Well, technically all coffee grows on trees.
The brown beans that go into making your morning cup are actually the dried and roasted seeds of a small red fruit from a tropical tree.
But on the better-managed coffee farms found in much of Central and South America, the plants are rarely allowed to grow much taller than a man. 
This channels the nutrients and energy that plants gather from the sun and soil toward producing beans, which make money, instead of wasting resources sprouting too many woody trunks and branches.
As most coffee is harvested by hand, keeping trees short also means that pickers can easily reach the fruits.
In Haiti, however, it's not out of the ordinary to find 20-foot-tall coffee plants.
...In fact, it is a sign of how long the country has been in crisis: Coffee is known as one of the best cash crops for a tropical farmer, especially one with a small plot of land who has few resources beyond hand tools, organic fertilizers, and sweat.
The majority of Haitians are farmers, and for the foreseeable future agriculture will remain the default economic backbone for the roughly six million people who live in rural districts.
Yet Haitian farmers put almost no energy into tending the small coffee groves that their fathers planted. 
The average yield in Haiti is now just a third of the Central American average..."