Stand-total tree-ring measurements and forest inventory documented climate-induced forest dynamics in the semi-arid Altai Mountains

Unbiased assessment of forest dynamics, including both tree radial growth and forest regeneration, for marginal forests is an urgent task in the context of widely reported forest decline and die-off caused by recent climate change. Based on a network of stand-total tree ring samplings and forest inventory data from eight stands, we reconstructed tree growth and forest recruitment dynamics during the past decades and investigated the linkages of forest dynamics to climate variations in the western and central Altai Mountains in the Inner Asian drylands. Our results revealed a strong coupling between tree growth, forest recruitment and climate variations. A favorable climate generally increases tree growth and triggers growth release and forest recruitments in these semi-arid forests. Differences in local environmental conditions, disturbance regimes and forest histories could possibly modify the forest recruitment dynamics among these forests. Tree radial growth and forest recruitments in both low and high altitudinal Altai Mountain show divergent responses to climate, especially to the spring temperature. A warmer spring will benefit forest recruitment but tends to limit larch radial growth at lower altitudinal mountains. Our study could provide insights into accurate predictions of forest dynamics in this huge mountainous region with complicated climate patterns.