Radial growth and its temporal stability of Dahurian larch in the southern boreal forest: Divergent trends during climate warming and warming hiatus

Climate warming has reshaped the structure and function of global boreal forest with expected negative impacts at its southern margins. A warming hiatus has occurred in many high-latitude regions in recent decades, but its impacts on tree growth in the southern boreal forest remain unclear. We sampled tree rings of Dahurian larch (Larix gmelinii) in the southern boreal forest of the Greater Khingan Mountains (GKM) and examined the trends of tree growth and its temporal stability based on the age-detrended basal area increment (BAI) for the periods of rapid warming (1962–1992) and warming hiatus (1993–2022). The results indicate that age-detrended BAI declined significantly during the warming period, while it showed no further decrease during the period of warming hiatus. Tree growth decline was associated with higher daily maximum air temperature in the main growing season and daily minimum air temperature in the non-growing season, as well as lower precipitation in the early growing season and daily minimum air temperature in the main growing season. During the warming hiatus, tree growth was positively regulated by the precipitation in the non-growing season, daily maximum air temperature in the early growing season, and daily minimum air temperature in the main growing season, but negatively affected by the daily maximum air temperature in the late growing season. Intriguingly, tree growth stability declined significantly during the warming period and recovered rapidly during the period of warming hiatus. The decline in tree growth stability was mainly explained by increasing daily minimum air temperature in the non-growing season. The recovery of tree growth stability was associated with lower precipitation in the non-growing season, higher interannual stability of daily maximum air temperature in the early growing season, higher interannual mean value and stability of daily maximum air temperature in the late growing season, and lower interannual mean value and stability of daily minimum air temperature in the main growing season. Our findings highlight a rapid recovery of tree growth stability instead of growth rate during the warming hiatus following a period of rapid warming and provide new insights into the decadal-scale resilience of the southern boreal forest in response to climate change.