Natural regeneration dynamic of mixed Nothofagus forests in southern Patagonia: influence of canopy composition and landscape

LENCINAS, MV; BLAZZINA, AP; SOLER, R; HUERTAS HERRERA, A; MARTÍNEZ PASTUR, G; TORO MANRÍQUEZ, M; PROMIS, A; MILLER, JA

Congreso; IUFRO Mixed species forests: Risks, resilience and management; 2020

Species composition of tree recruitment in mixed forests is a determining factor related tothe canopy structure. This work determine if the mixed forests of Nothofagus pumilio and N.betuloides present transitions towards forest types with the dominance of one of thesespecies or are a stable system, by the analyses of its natural regeneration dynamics. Threeforest types were selected (pure N. pumilio, pure N. betuloides and mixed stands) in twocontrasting locations (coasts and mountains) in Tierra del Fuego, Argentina. Forest structureand microclimate (air temperature, soil moisture) were evaluated for each stand (n=12),while seed production and natural tree regeneration were monitored annually (2014-2019).Data were analysed with ANOVAs, general linear models and multivariate techniques.Seedling recruitment of N. pumilio and N. betuloides was proportional to seed productionwith significant inter-annual variability. Nothofagus pumilio was more successful in seedlingsrecruitment in every forest types and locations. The difference for both species in the mixedforests was also significant, with greater quantity of seeds and seedlings for the N. pumiliospecies. Forest structure and climate also played important roles in dynamics of mixedNothofagus forests. Multivariate analyses revealed a stronger effect of landscape ratherthan of canopy composition. Our results show a tendency in mixed Nothofagus foreststowards a transition to pure N. pumilio forests, mainly due to a greater success in itsregeneration strategy.