Microclimatic Conditions Restrict the Radial Growth of Nothofagus antarctica Regeneration Based on the Type of Forest Environment in Tierra del Fuego

G MARTÍNEZ PASTUR; J RODRIGUEZ SOUILLA; MV LENCINAS; JM CELLINI; JE CHAVES; MC ARAVENA ACUÑA; FA ROIG; PL PERI

Sustainability

MDPI

Lugar: Basel; Año: 2023 vol. 15

2071-1050

Regeneration is crucial for forest continuity in natural and managed stands. Analyzingintra-annual dynamics can improve the understanding between growth and climate, identifyingregeneration survival thresholds. The objective of this study was to determine the microclimateconstraints (rainfall, air, and soil temperatures) of Nothofagus antarctica regeneration growth in closed,open, and edge forests in Southern Patagonia. We measured stand characteristics (forest structure,understory plants, soil properties, animal use), microclimate, and the daily growth of regenerationusing dendrometers (n = 6) during two growing seasons. We found significant differences in thestudied variables (e.g., overstory, light, soil, understory plants, animal use) in the following order:closed primary forests > open forests > edge forests with openlands. These changes defined themicroclimate across the overstory gradient (e.g., soil moisture), influencing the daily growth ofregeneration across the growing season (lag, exponential, stationary). Rainfall (the F factor variedfrom 6.93 to 21.03) influenced more than temperature (the F factor varied from 0.03 to 0.34). Dailygrowth in closed forests indicated shrinkage (􀀀0.0082 mm day􀀀1 without rain and 􀀀0.0008 mmday􀀀1 with 0.0–0.2 mm day􀀀1 rainfall), while for more than 0.2 mm day􀀀1 of rainfall, growth alwaysincreased. Open forests presented shrinkage during days without rain (􀀀0.0051 mm day􀀀1), showingpositive growth according to rainfall. Edge forests always presented positive daily growth. Theresilience of regeneration under these changed conditions was directly related to the overstory. Themain outputs indicated that regeneration was vulnerable during non-rainy days at the middle orclosed overstory (>40% crown cover), suggesting the need for long-term monitoring to develop bettersilvicultural proposals.