Multiple climate signals in quantitative wood anatomical measurements of Rocky Mountain bristlecone pine

Keywords: climate, dendrochronology, paleoclimate, drought
Session Type: Virtual Paper Abstract
Day: Monday
Session Start / End Time: 2/28/2022 02:00 PM (Eastern Time (US & Canada)) - 2/28/2022 03:20 PM (Eastern Time (US & Canada))
Room: Virtual 28

Abstract

Recent temperature increases in the southwest United States are exacerbating drought, limiting water availability, and disrupting arid ecosystems. Prior research has used tree-ring data from Rocky Mountain bristlecone pines (P. aristata) to reconstruct past climate in this region. However, these trees show a mixed temperature-moisture response, making reconstructing past temperature a challenge. In order to find a robust temperature signal in southwest trees, we investigate the physiological linkages between P. aristata and climate variability. We develop very high-resolution centennial-scale tree-ring data from two sites in the Southern Rocky Mountains by a quantitative wood anatomical approach. Using cell anatomical measurement chronologies and gridded climate data, we identify robust correlations between select anatomical chronologies and temperature. At the high elevation site, anatomical maximum latewood density has a significant positive (r=0.53) relationship with August maximum temperature. Earlywood lumen area shows a significant negative (r=-0.61) correlation with June-July maximum temperature at the high elevation site, isolating a negative influence of high temperatures in the early part of the growing season. Latewood radial cell wall thickness at the high elevation site has a significant positive correlation (r=0.4) with Aug-September maximum temperatures over the full 1917-2017CE period, but the correlation begins to decouple in the 1980s. Low elevation site cell chronologies have similar relationships with maximum summer temperatures. Across both sites, these correlations with temperature are met with similar yet inverted correlations with precipitation, indicating that the temperature-moisture response is mixed even at the cellular scale.