Changes in tree diversity and structure of a temperate forest under two silvicultural treatments in Durango, Mexico

Introduction: Forest diversity and structure are important attributes that can be modified by silvicultural treatments. Objective: We compared tree diversity and structure of a temperate forest under the silvicultural treatments of selection and thinning in El Salto, Pueblo Nuevo, Durango. Materials and methods: The Shannon diversity index of six sites treated with the selection method and six with thinning was determined in three inventories over a period of 10 years. The diversity among treatments was compared for each inventory using Hutcheson's t-test for similarity or difference in diversity-abundance. For each treatment and for the 12 sites, the ecological parameters (abundance, dominance and frequency), importance value index (IVI) and forest volume were analyzed with Kruskal-Wallis tests to determine differences between inventories. Results and discussion: A total of 18 species were recorded in the three inventories; Pinus cooperi, P. durangensis and Quercus sideroxyla had the highest IVI. In each inventory, Hutcheson's t-test indicated that diversity was significantly higher (P < 0.05) in the selection treatments. On the other hand, in each treatment, the Kruskal-Wallis test showed no significant differences (P > 0.05) in the ecological parameters between inventories; furthermore, tree density, basal area and forest volume of each site showed no significant differences between inventories. Conclusion: Diversity was higher for the selection treatment. The ecological parameters were not different between inventories, so the forest structure was not affected at the time of intervention.