March 2021

Back To The Future With Tree-Ring Standardization: Maybe Schulman Did It The Right Way

This talk reflects over 45 years of research and contemplation by me on the tree-ring standardization problem. There is no optimal solution to this problem because the statistical properties of the raw ring-width data we typically process are very complicated and their expressions of radial growth over time are totally unobserved. It has recently become apparent to me that we spend too much time letting the computer do the standardization for us without taking time to look at the data.

Connecting tributary erosion to downstream floodplain forest establishment in a large river network

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-Ring Day

Join us for a series of public talks by our graduate students!

Schedule:

10:30 — Opening Remarks (David Frank)
10:45 — Live 3-minute Lightning Talks

Living with the star: Carbon-14 excursions in tree rings as the evidence for extreme solar activity

The annual 14C data in tree rings is an outstanding proxy for uncovering extreme solar energetic particle events (SEP, also called SPE -solar particle event) in the past. Signatures of extreme SEP events have been reported in 774/775CE, 992/993 CE, and ~660 BCE.

Tree-rings to biomass trajectories: uncertainty and fading records

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.