CARACTERIZACIÓN FLORÍSTICA DEL BOSQUE MONTANO Y SUBPÁRAMO DEL VOLCÁN IRAZÚ, COSTA RICA.

Irazú volcano is one of the highest peaks in Costa Rica; it constitutes one of the few sites with the plant association known as montane and sub-paramo. The research aimed to characterize the structure and composition of this ecosystem considering two altitudinal floors (montane and subpáramo). Three 1000 m² plots per forest type were established, in which botanical identification was developed, and diameter and total height were measured. In both forests, the diameter distributions were adjusted to the different forest models with a basal area of 31.68 m² ha¹ in montane forest and 4.67 m² ha¹ in subpáramo forest. Regarding the vertical structure, the montane forest reached a maximum height of 21 m with three well-defined strata; on the other hand, the subpáramo reached 8 m and did not differentiate strata. Regarding the diversity analysis, it was determined that both forests have significant differences; the montane forest reported 20 species, while the subpáramo only had six species. Comarostaphylis arbutoides is the most important species for both communities. The most important conclusion is that the study area can be considered an altitudinal island; it represents a site of high value for the conservation and research of the sub-paramo plant community. The structure is straightforward in species, its area is minimal, and it is very vulnerable to volcanic events, which shows its value for conservation and study. [ABSTRACT FROM AUTHOR]