Long-term monitoring reveals the effect of precipitation and silviculture on Nothofagus regeneration in Northern Patagonia mixed forests

SOLA, GEORGINA; MATEO, CAMILA; DEZZOTTI, ALEJANDRO; MARCHELLI, PAULA; ATTIS BELTRÁN, HERNÁN; SBRANCIA, RENATO; CHAUCHARD, LUIS; GONZÁLEZ PEÑALBA, MARCELO; LARA, MARTÍN; EL MUJTAR, VERÓNICA

Ecological Processes

Springer

Año: 2024 vol. 13

Background Tree regeneration is a key component of resilience because it promotes post-disturbance recoveryof forests. Northwestern Patagonia from Argentina is occupied by Nothofagus alpina (Na), N. obliqua (No), and N.dombeyi (Nd) forests that grow along an intense precipitation gradient, managed throughout shelterwood silvicultural system by technicians of the Lanin Natural Reserve. The objective of this study was to evaluate the infuenceof seeding cuttings over the dynamics of Nothofagus mixed forests across landscape (precipitation gradient) basedmainly on the composition and abundance of tree regeneration, permanent sampling plots and generalized linearmixed models. In particular, we analysed: (i) the structure of sexual and asexual regeneration during20 years after harvest (the dynamics of managed forests), and (ii) the structure of sexual regeneration in primaryand managed forests after>20 years of harvest (the efect of silviculture).Results Nd was the most abundant species in the regeneration of managed forests during all periods in both sitesdespite its lower contribution to the adult cohort. During the 10–20 years period after harvest, the humid siteexhibited higher regeneration density than the mesic site (120,000 and 6000 ind ha−1, respectively), and it decreasedafterwards. The number of established regeneration (>2 m height) was lower for Na in the mesic site and for Noin the humid site (0 and 57 ind ha−1, respectively). However, in comparison to No, Na showed a higher numberof sprouted stumps and sprouts per stump, and a higher sprout height in the mesic site. No exhibited higher sproutmortality in the humid site. Finally, the regeneration of primary forests showed lower density and height, and a morebalanced composition than that of managed forests.Conclusions The silvicultural efects on the mixed forest regeneration dynamics was strongly infuenced by the condition of sites. Therefore, management prescriptions should be adjusted in order to consider the environmentalvariation occurring through the entire landscape. An adaptive management that considers the pattern and processof sexual and asexual regeneration and disturbance will contribute to promote a greater resilience of mixed forestecosystems.