1. How Soil
Correlates with
Tree Distribution
and Diversity
James
Biddle

2. Special Thanks
➔Sean McMahon
➔Geoffrey Parker
➔Jessica Shue
➔Ben Turner
➔Laureen Echiverri
➔Dan Gustafson & Lauren Nuzzi

3. Outline
➔Overview of Summer Work
➔A Focus on Nutrients and Productivity
➔Questions and Hypothesis
➔Methods
➔Findings
➔Conclusion and Future Directions

4. So What?
● Is there an impact of soil nutrients on
the distribution of tree species at
SERC?
● What other factors influence tree
dispersal?
● Why does this matter?

5. The Projects
● SI-GEO Soil Carbon Census
● Dendrometer Band Sampling
● Innovative Photo-Based Tree
Measurement
● Weekly Micro Cores of Beech
Trees

6. ForestGEO Network

7. Sixteen Hectares.
Four Hundred Forty-Eight Samples.

8. Collection Methods
● 1-2 People in the Field
● Drilling Through Mud, Clay,
Sand, Roots, Rocks

9. Processing Methods
● Soil Collected
● Removed roots and measured
weight
● Measured soil moisture
● 50g samples sent to STRI

10. Carbon Project Future
● Carbon content analyzed
● Spatial maps
● Further analyses of tree
diversity and soil interactions

11. Soil Nutrient Collection Sites

12. SI-GEO
Topography

13. Distribution
of Moisture

14. Correlation
Between
Soil
Moisture &
Elevation

15. Technical Terms
● Effective Cation Exchange Capacity (ECEC) is the
amount of exchangeable cations found on solid soil
particles
● These cations are Ca, Mg, Na, and K, and many
others
● Resin bags in the soil collect the nutrients floating in
the soil solution instead of the solid particles
● Focusing on Calcium collected using the resin bag
method

16. Distribution
of ECEC

17. Distribution
of Calcium

18. Distribution
of
Phosphorus

19. Distribution
of Water pH

20. Distribution
of Calcium
and
Sweetgum

21. Distribution
of Water pH
and Tulip
Poplar

22. Distribution
of ECEC and
American
Beech

23. Distribution
of Water and
Spicebush

24. Conclusions
"Correlation is not causation...”
“but it sure is a
hint.”- E.R. Tufte
● Many variables affecting tree distribution
● Strong relationship between moisture and
dispersal
● Nutrients have impact, easier to see in flat areas

25. Next Steps
● More complete picture of what impacts tree
dispersal with integration of soil carbon
census
● Further data analysis could reveal exciting
correlations
● New connections within nature
● Comparisons to other Forest GEO plots

26. Questions?