What do trees remember? Perspectives on biological memory in dendrochronology

Keywords: dendrochronology, forest ecology, paleoclimate
Session Type: Virtual Paper
Day: Friday
Session Start / End Time: 4/9/2021 04:40 PM (Pacific Time (US & Canada)) - 4/9/2021 05:55 PM (Pacific Time (US & Canada))
Room: Virtual 30

Abstract

It has been widely-established by dendrochronologists that tree ring measurements express significant temporal autocorrelation across multiple years of growth. The origin of this autocorrelation has alternately been attributed to either the legacy effects of abrupt environmental change on tree growth, or to long-term ocean-atmosphere and land-surface processes. In the former case, hereafter referred to as “biological memory” autocorrelation is considered the result of external influences on the long-term accumulation of photosynthates. In the latter case, referred to here as “climate persistence,” autocorrelation is considered the expression of low-frequency variability stemming from climate and environment. In applications ecological contexts, biological memory represents the signal of forest growth responses to environmental shocks. By contrast in dendroclimatology, temporal autocorrelation is considered to be non-climatic noise and is often removed during chronology development if it does not mimic the low-frequency patterns exhibited by instrumental records. Here, we consider how diverging perspectives on the sources of temporal autocorrelation affect research outcomes in dendrochronology. We advance a conceptual framework for disentangling biological memory from climatic persistence, and discuss the potential effects of differing assumptions regarding the sources of multi-year autocorrelation for analysis in forest ecology and paleoclimatology. We hope to elucidate the ways in which autocorrelation is conceptualized and treated in tree ring research, and to highlight areas of agreement and tension present in between these two perspectives.