Dartmouth Events

(Subcritically) cracking the critical zone

[When Earth, wind, water and trees connect] Earth Sciences Seminar. Dr. Jill Marshal is from The University of Arkansas, the event is from 1:10pm to 2:10pm

Thursday, November 17, 2022
1:00pm – 2:15pm
Wilder 115
Intended Audience(s): Alumni, Faculty, Postdoc, Staff, Students-Graduate, Students-Undergraduate
Categories: Arts and Sciences, Lectures & Seminars

In thin-soiled settings, we presume that trees play a significant role in converting rock into mobile sediment via physical weathering, with models centered on tree throw. However, little is known regarding how - or how often - trees damage rock. Combining novel force sensors at the tree-rock boundary with precipitation, solar radiation, wind, tree sway data, and acoustic emission sensors I have begun to quantify tree-driven soil-production mechanisms. Charismatic tree throw may matter less than belowground damage. Results suggest that while wind forces matter, conifers bang repeatedly on rock while bendy deciduous trees can dampen wind loads significantly. Field data and physical modeling shows that even daily root water uptake can generate significant cracking. Finally, I will posit (speculate wildly) that current soil production functions should be recast to consider a 'Middle Earth' soil production function -one that combines eco-geomorphology above with non-steady fracture mechanics from below, which might explain both the humped and exponential soil production functions.

To view our entire list of Fall seminars see our webpage.

For more information, contact:
Marisa Palucis

Events are free and open to the public unless otherwise noted.