Structural analysis of the forest mass of the tropical dry forest of the Luis Vargas Torres Technical University of Esmeraldas.

Abstract

In the forest of the Mutile experimental station at the Luis Vargas Torres Technical University of Esmeraldas, a study was conducted in 2002 to analyze the structure of the forest mass, the horizontal and vertical structure, natural regeneration, diametric distribution, and diversity indices. A stratified systematic sampling design was applied considering altitudinal levels, with a sampling intensity of 0.98%, 0.84%, and 0.79% respectively, obtaining a sample size of 20,000 m2 per stratum, recording all individuals with a DAP ≥ 10 cm, identifying 2,640 individuals distributed across 57 species belonging to 32 families. The study highlighted the most abundant species: Ocotea sp. with 9.92%; Tryplaris guayaquilensis 9.36%; Palmaceae 9.02%; Castilla elastica 8.83%; Talisia sp. 6.55; and Brosimum guianense 6.25%; those of greatest occurrence and distribution; Castilla elastica, Ocotea sp., Palmaceae, Talisia sp., Tryplaris guayaquilensis, Erythrina poeppigiana; among the most dominant are: Castilla elastica 14.38%; Tryplaris guayaquilensis 14.00%; Talisia sp. 12.88%; Brosimum alicastrum 12.48%; Erythrina poeppigiana 12.06%; Coussapoa rotunda 9.28%; The species with the greatest ecological weight IVI, stand out: Castilla elastica with 8%; Tryplaris guayaquilensis 7.98%; Ocotea sp 7.01%; Talisia sp 6.77%; Brosimum alicastrum 5.69%; Regarding the vertical structure, the species are mostly represented in the middle stratum with 61.83%; the lower stratum with 21.62% and the upper stratum with 16.55%, ensuring the natural succession of species. The diametric distribution shows that the largest number of individuals is located in category I with 43.5%, category II with 26.17%, category III with 9.5%, and categories IV and V with 4.9%. Additionally, species categorized as present include: Palmaceae, naranjillo, and papayo, which are located at 10.9%. Graphically, the diametric distribution indicates an inverted U-shape, demonstrating that the succession of species is ensured; however, the natural regeneration found in the area was very scarce, considering climatic and anthropogenic factors, as well as the lack of good silvicultural management. The analysis of alpha diversity showed the species richness in intracommunity aspects highlighting stratum III (200.1 – 300 masl) with 6.19; stratum I (30 – 100 masl) with 5.03 and stratum II (100.1 – 200 masl) with 4.98. The results of Beta Diversity indicate that there is similarity between stratum I - II, unlike the strata I - II and II - III. The consolidated analysis for the diversity calculation through the Shannon index yielded a result of 3.18 demonstrating high diversity and species richness in the study area.