Tree Radial Growth and Vegetation Dynamics in Northern China and Northern Patagonia Regulated by Ocean–Atmosphere Circulation

Abstract

Increasing climatic pressures on global forest ecosystems highlight the urgent need to quantify their responses to climate change. This study integrates tree-ring chronologies, Normalized Difference Vegetation Index (NDVI), and climate reanalysis data to investigate vegetation-climate interactions and the role of ocean-atmosphere circulation in mid-latitude Pacific regions. We developed new chronologies for Pinus tabuliformis in northern China and Araucaria araucana in northern Patagonia Argentina, revealing distinct response mechanisms under global warming. Recently, both regions have exhibited rapid tree radial growth, although the growth of A. araucana in northern Patagonia remains comparatively weaker. P. tabuliformis growth is closely aligned with monsoon precipitation and maintains significant correlations with local NDVI; likewise, A. araucana growth also responds high sensitively to local moisture variability and exhibits stronger coupling with NDVI over the northern Patagonian Plateau during the summer months. Favorable thermal conditions combined with adequate precipitation or snowmelt during spring and summer driver tree growth in both regions. Over the past century, evolving teleconnection patterns suggest that the El Niño-Southern Oscillation (ENSO) has had a diminishing negative impact on P. tabuliformis growth while exerting an increasingly persistent and intensifying positive influence on A. araucana. The Arctic Oscillation (AO) and Southern Annular Mode (SAM) also exhibit significant temporal variations in their impacts across both regions. The findings suggest that the observed forest resilience in northern China and Patagonia represents a crucial ecological positive feedback mechanism, particularly for developing climate adaptation strategies against intensifying heatwaves and drought events.

Keywords: Temperate forests ecosystems, Tree rings, Climate-growth response, Normalized Difference Vegetation Index (NDVI), Ocean-atmosphere circulation