Soils in these hills are shallow, well-drained, alkaline and interspersed between outcrops of hard limestone. Mean annual precipitation varies from 15O to 2OO centimeters. Two strata are present in this type of forest. The upper strata is composed of a continuous layer which extends up to 2O meters in height with a few emergent trees reaching 25 meters. The second strata reaches 1O meters in height and the number of deciduous species is low.
Most species are evergreen, with simple, microphyllous leaves.
Palm species may be common in this strata. The understory includes species such as Eugenia biflora , E . foetida , E . Palo de nigua is also found near Barranquitas on Monte Torrecilla, an area which is volcanic in origin, at an elevation of 94O meters. The vegetation of this area has been classified as lower montane forest in the subtropical moist forest life zone. Historically, deforestation and selective cutting for agriculture, grazing, production of charcoal, and the cutting of wood for construction materials have affected palo de nigua.