The pecan tree, what makes the desert livable

If you have ever arrived at a hacienda in northern Mexico in the middle of July, you remember the exact moment you stepped under the pecan trees. The temperature drops several degrees at once. That is not an impression: it is physics, and it explains why these trees are where they are.

A tree that manufactures its own climate

The pecan is a large tree with a wide crown and dense foliage. Under its shade, direct radiation is almost entirely blocked, and transpiration from the leaves cools the surrounding air.

In a climate where the sun is the main problem, planting pecans is a decision about livability before it is an agricultural one. Haciendas planted them around the main houses and along the roads because they made summer possible.

Mexico, a pecan power

Mexico is one of the world's leading producers of pecans, and the northern states account for most of the planted area. Coahuila is part of that producing belt along with Chihuahua and Durango.

The pecan is native to the Mississippi basin and northern Mexico, so it is not a crop forced into place: it grows where it evolved.

What to know if you will have pecans

They are slow. A pecan begins producing around its sixth or seventh year and reaches full production considerably later. Whoever plants pecans is not harvesting for themselves in the short term. Like a vineyard, it is a tree you plant thinking of whoever comes next.

And they are long-lived. A well-tended pecan produces for decades. Many of the trees giving shade today at Coahuila's haciendas were planted by people who are no longer here.

They want water. That is their real cost. The pecan is a bottomland tree, accustomed to deep soils with available water, and in an arid climate that means irrigation. Modern systems, drip irrigation and soil moisture monitoring, have improved efficiency considerably, but the pecan will never be a low-consumption crop.

The harvest

Pecans are harvested in autumn, between late October and December. In commercial orchards, machines shake the trunk and the nuts fall onto tarps.

In family orchards it is still done with a pole and patience, which is one of those activities that brings several generations around the same task.

In the Amargos landscape

At Ex-Hacienda Amargos the pecans are part of the land's inventory, and several lots include them within their boundaries. They are not added ornament: they were here before the project, and their shade already defines where it is pleasant to walk in summer.

Keeping them was a decision about layout. It is simpler to subdivide across a clean flat, but a mature pecan cannot be replaced: it would take decades to have again what is already standing.