Varying climate signals embedded in latewood blue intensity along an elevational gradient: A multi-species case study from the Great Basin, Nevada, USA

Abstract

As blue intensity (BI) methods are increasingly employed to generate temperature-sensitive tree-ring records around the globe, the influence of intra-site variation in elevation on climate-growth relationships for BI parameters remains largely unresolved. Here, we develop six latewood blue intensity (LWBI) chronologies along an elevational gradient for two montane conifer species, Abies concolor var. concolor (Gordon & Glend.) Lindl. Ex Hilderb and Picea engelmannii Parry ex Engelm., growing in the arid southwestern United States. In this first documented study to examine the climate response of LWBI from A. concolor, we find positive, significant (p < 0.05) correlations between the LWBI chronology from the highest elevation plot and spring–summer temperatures (April–August, r > 0.46). Moreover, the positive temperature response of A. concolor is generally stronger and more temporally stable than for P. engelmannii across varying seasonal windows. In comparing the differences in climate response across species and elevation, we document distinct clinal relationships between the temperature response of LWBI for A. concolor, where both the strength and temporal stability of the positive temperature signal increases with elevation. Meanwhile, the mid-elevation P. engelmannii demonstrate the highest climate sensitivity. As such, our findings contribute to a more comprehensive understanding of how elevation influences the type and strength of the climatic information embedded within the LWBI parameter from arid, montane conifers growing near their historical range margins.