Regional Characteristics of the Climatic Response of Tree-Ring Maximum Density in the Northern Hemisphere

Abstract

The maximum latewood density (MXD) of tree rings can reflect the temperature of the growing season, but the timing of the response differs among regions. We selected 152 maximum latewood density chronologies from the Northern Hemisphere that showed a significant response to temperature. Based on a cluster analysis and the sensitivity of MXD to the monthly mean temperature, the chronologies were classified into six clusters. The clusters showed distinct regional characteristics, and the period and peak month of significant response of the chronologies in each cluster to temperature were different. Spatial synchronization of the MXDs revealed that the two clusters distributed in Europe showed the most consistency and the strongest response to the April–September monthly mean temperature compared with the other clusters. Temperature accounted for more than 40% of the total MXD variance in all clusters, whereas the effect of precipitation was much smaller. In addition to climatic factors, the random effect of the latitude and longitude of sampling sites, elevation, and tree species was a major factor contributing to the variance in MXD in each cluster. Latitude and longitude had the strongest influence among the three random effects, and tree species had the weakest influence, except at high latitudes. The MXD of each cluster showed sensitivity to temperature within a certain interval, with a positive linear response, and the sensitivity interval was greatest at high latitudes. Certain clusters showed a negative linear sensitivity to precipitation. The results provide a reference for studying the climatic threshold of large-scale tree-ring density formation.

Interconnections of Climate, Vegetation Index, and Tree Growth: Insights Into Samur-Yalama National Park, Azerbaijan

“…Cook et al [2004] conducted a comprehensive dendroclimatology study examining the sensitivity of tree-ring growth to climate variability, highlighting the significance of temperature fluctuations in driving tree growth dynamics. Cook et al [1999], Liu et al, [2019], Roibu et al, [2020], Yu et al, [2023] etc. conducted dendroclimatic analyses and observed a significant sensitivity of tree growth to temperature variations.…”