Roble vs. alcornoque vs. encina

While the Spanish words 'roble', 'alcornoque', and 'encina' all refer to types of oaks, they denote different species with unique features and attributes.

Roble

Becomes highly significant to the term oak. This word is used universally to indicate a range of oak species. It's usually related to trees known for their strength, durability, and high quality wood.
El roble es un árbol muy fuerte y duradero.
(The oak is a very strong and durable tree.)
La madera de roble es una de las más utilizadas en la construcción de muebles.
(Oak wood is one of the most used in furniture construction.)

Alcornoque

Refers specifically to cork oaks, typically found in southwestern Europe and northwestern Africa. These trees are known for their thick, corky bark from which natural cork is harvested.
El alcornoque se utiliza para la producción de corcho.
(The cork oak is used for cork production.)
La corteza del alcornoque se regenera después de cada recolección.
(The bark of the cork oak regenerates after each harvest.)

Encina

Refers specifically to holm oaks or holly oaks. Unlike other oaks, these trees are evergreen with small, stiff leaves somewhat similar to those of holly. They are common in Mediterranean region.
Las encinas son árboles perennes que conservan sus hojas durante todo el año.
(Holm oaks are evergreen trees that keep their leaves all year round.)
La encina proporciona alimento a muchas especies animales gracias a sus bellotas.
(The holm oak provides food for many animal species thanks to its acorns.)

Summary

In summary, while 'roble', 'alcornoque', and 'encina' all refer to species of oak in Spanish, each term represents specific traits and characteristics. Roble refers broadly to many varieties of oak; alcornoque denotes the cork-producing species; and encina symbolizes an evergreen variety that thrives in Mediterranean climates.