Overcoming model instability in tree-ring-based temperature reconstructions using a multi-species method: A case study from the Changbai Mountains, northeastern China

Abstract

Abstract. The unstable sensitivity of growth-climate relationships greatly restricts tree-ring-based paleoclimate reconstructions, especially in areas with frequent divergence problems, such as the temperate zone in northeast China. Here, we propose an original tree-species mixing method to overcome this obstacle and improve the stability and reliability of reconstruction models. We take the tree-ring based growing-season minimum temperature reconstruction for the northern Changbai Mountains in northeast China as an example to illustrate the method. Compared with previous temperature reconstruction models, our reconstruction model is more stable and reliable and explains up to 68 % of the variance. It is also highly consistent with historical records and tree-ring-based temperature reconstructions from the nearby Xiaoxing'an Mountains and from across the Northern Hemisphere. Our reconstruction uses two different tree species and is more accurate than temperature reconstructions developed from a single species. Over the past 259 years (AD 1757–2015), five significant cold periods and five warm periods were identified. The reconstruction indicates rapid warming since the 1980s, which is consistent with other instrumental and reconstructed records. We also found the Atlantic Multidecadal Oscillation plays a crucial role in driving the growing-season minimum temperature in the northern Changbai Mountains.

Comment on cp-2021-2

“…As previous studies have shown, P. koraiensis and F. mandshurica show contrasting response patterns to rapid warming (Cao et al, 2018;Zhu et al, 2015b;Zhu et al, 2020b;Wang et al, 2016). In the case of P. koraiensis, temperature sensitivity is slightly weakened after warming (Zhu et al, 2015b). This divergence phenomenon has been reported by many studies, especially in northern forests (D'Arrigo et al, 2008;Zhu et al, 2018a).…”

“…This divergence phenomenon has been reported by many studies, especially in northern forests (D'Arrigo et al, 2008;Zhu et al, 2018a). Although many previous tree-ring studies from the surrounding area have suggested that this divergence phenomenon is associated with temperature-induced drought stress (Zhu et al, 2018a;Zhu et al, 2015b), the exact causes are still unknown. Other possible causes include nonlinear thresholds or time-dependent responses to rapid warming, the delayed snowmelt and related changes in seasonality, the differential growth-climate relationships inferred for mean, maximum, and minimum temperatures, and global dimming (D'Arrigo et al, 2008).…”

“…The unstable sensitivity of P. koraiensis or F. mandshurica to temperature (Fig. 3) has been proved widespread in northeast China (Cao et al, 2018;Zhu et al, 2015b;Zhu et al, 2020b;Wang et al, 2016). Hence, previous temperature reconstructions based only on tree-ring widths of P. koraiensis (Zhu et al, 2009;Shao and Wu, 1997;Lyu et al, 2016) or F. mandshurica Wang et al, 2012;Yu, 2019) may have some uncertainty.…”

“…The two temperature records (CB and LB in Fig. 6) in Changbai Mountains were both based on tree-ring widths of P. koraiensis (Zhu et al, 2009;Lyu et al, 2016), which is known to have an unstable growth-climate relationship (Zhu et al, 2015b). There are two temperature records based on the ring widths of F. mandshurica for the Changbai Mountains (Yu, 2019;Wang et al, 2012), but we were unable to access these records.…”