STAND STRUCTURE AND TREE DIVERSITY IN THREE LAND MANAGEMENT SYSTEMS IN PALMAGTITAN, SIERRA NORTE DE PUEBLA

Abstract

Background. Agriculture and cattle raising are the main factors to forest loss and fragmentation, therefore, to reduce their negative impact, new production systems have been implemented. The Agroforestry and Silvopastoral Systems are corridors for fauna and source of natural regeneration, promoting the coexistence of several species and providing goods and services to the human being. Until now, the effects of the agriculture and cattle raising in the composition and configuration at the humid tropical forest in Sierra Norte de Puebla are still unknown. Objective. To compare the changes in the composition, stand structure, richness and tree diversity between an Agroforestry System (AFS), Silvopastoral System (SPS) and a Second-Growth Forest (SGF) in Palmagtitan, Sierra Norte de Puebla. Methodology. We established sampling units in three land management systems where we recorded specie, normal diameter total height, and cover of every tree in the area. For each attribute, we generated categories. The stand structural attributes such as density, basal area, cover and normal diameter were calculated and compared between land management systems with the multiple comparison DGC method. We obtained and compared the Margalef’s richness, Shannon’s diversity, Equitability and Fisher’s alfa indices and Hill’s numbers. The floristic similarity was analyzed with the Sorensen coefficient. Results. We identified 44 species from 24 families. The families Burseraceae, Moraceae, Rutaceae, Euphorbiaceae and Fabaceae were the best represented. Only the tree density presented statistical differences between the land management systems. The Margalef’s richness index was different only in the SPS. The Shannon’s diversity index and the Hill’s numbers showed a major diversity in the AFS than in the SGF and the SPS. The similarity in the floristic composition between AFS and SPS was 16.6%, between AFS and SGF 38.30% and between SPS and SGF 26.23%. Implications. The characterization of the stand structure and tree diversity permits a better decision-making about the production systems management and the forest patches conservation. The tree management and the presence of native species in production systems allow to integrate handling practices to provide food safety and biodiversity conservation. Conclusions. The composition, stand structure, richness, and tree diversity in the three land management systems were determinated by the management and land use history. As the expected, the SGF got the biggest density, but (contrary to the stipulation) the most diverse was the AFS. It is necessary to know the ecosystems configuration and composition to devise management strategies that allow us to integrate the production and ecosystems conservation.