Effect of Individual Selection Silvicultural Treatment on the Vertical Structure of a Pine-Oak Forest in Northern Mexico

Understanding the structural dynamics of temperate forests is essential for their sustainable management. This study assessed the vertical structure of a mixed temperate forest in the Sierra Madre Occidental, Mexico, under an individual selection cutting regime implemented in 2012 and 2022. Nine Permanent Silvicultural Research Sites were established, and measurements were carried out in 2012, 2022, and 2023 to record tree species, height, and crown cover. The analyses describe dendrometric variables, structural verticality indices and the Pretzsch index; regression models were fitted and Kruskal–Wallis tests performed. The results revealed a multistratified forest: Pinus durangensis dominates the upper canopy, while broadleaved species concentrate in the lower layers, enriching the understorey. Following silvicultural interventions, structural reorganisation was evident, with an increase in emergent individuals in the canopy and stability in crown-cover frequencies. A slight increase in pine and oak cover was detected, together with the presence of new tree species characteristic of the region. Taken together, the findings indicate that planned individual-selection cutting can maintain the stand’s original vertical structure and the functionality of the mixed temperate forest in northern Mexico, providing an analytical approach applicable to other comparable forest regions.