Search for: All records

Summary Tree rings are considered the gold standard for observing variation in past atmospheric radiocarbon (¹⁴C), yet little attention has been paid to whether different trees record tropospheric¹⁴C evenly. The discovery of Miyake events, rapid increases in¹⁴C production occurring in past millennia, has led to repeated measurements of¹⁴C in tree rings across species and locations. These records demonstrate remarkable synchrony, yet significant variability between samples remains, limiting reliable use of tree rings as a precise indicator of the timing and scale of past¹⁴C production. Understanding how trees and species record tropospheric¹⁴C would improve reconstructions of past¹⁴C production events, refine geochronological control, and because of the pulse‐like nature of past¹⁴C production events, shed light on a fundamental question in tree physiology and dendrochronology: what is the lag time between photosynthesis, storage, and allocation to wood and how might this lag blur isotopic signals in tree rings? Here, we evaluate the implicit assumption that all trees record tropospheric¹⁴C evenly by focusing on the path carbon takes within trees including: phenology of carbon uptake and wood formation, storage and use of nonstructural carbohydrates, and how these factors interact to affect the tropospheric¹⁴C signal in wood. 

Rapid Arctic environmental change affects the entire Earth system as thawing permafrost ecosystems release greenhouse gases to the atmosphere. Understanding how much permafrost carbon will be released, over what time frame, and what the relative emissions of carbon dioxide and methane will be is key for understanding the impact on global climate. In addition, the response of vegetation in a warming climate has the potential to offset at least some of the accelerating feedback to the climate from permafrost carbon. Temperature, organic carbon, and ground ice are key regulators for determining the impact of permafrost ecosystems on the global carbon cycle. Together, these encompass services of permafrost relevant to global society as well as to the people living in the region and help to determine the landscape-level response of this region to a changing climate.