Tree-Ring Talk

During the twelfth century A.D. Indigenous societies across the Mississippi River Basin transformed: populations aggregated into towns around dramatic monumental constructions that represented the seat of polities, communities adopted foreign styles, and more centralized leadership roles emerged. While the general outline of Mississippian history is known, exactly how people came to abandon old cultural practices in favor of the Mississippian pattern is not understood, nor are the historical details of individual mound centers.

The Mediterranean region is projected to experience severe drying trends and more extreme hydroclimate events as a consequence of anthropogenic climate change over the next century.   In some places, this signal may have already emerged from natural variability.  Here we provide content for recent and future changes using new high-resolution spatial reconstructions of multiple hydroclimate fields from a tree-ring network that spans the last millennium.

Sediment eroded from the headwaters of a large basin strongly influences channels and ecosystems far downstream, but the connection is difficult to trace. Disturbance dependent riparian trees are thought to rely upon floods for creation of the sand bars necessary for establishment, but pulses of sediment should also promote formation of this habitat.

Tree-rings provide evidence of past aboveground carbon storage that can be used to inform and constrain ecosystem model predictions. However, formal state data assimilation requires the characterization of the uncertainty associated with the data being assimilated. In addition, aboveground biomass reconstructions from living trees typically suffer from the fading record problem- that trees that once contributed to the aboveground biomass pool may have died.