This is non-trivial since only the large stems have C fraction data.
Slice 1: Include all traits except C fractions as predictors plus size, using as many samples as possible
Slice 2: Include all traits as predictors, exclude small stems for which there is no C fraction data
does this also include traits_explain_pmr.pdf and traits_explain_pmr.pdf? Be pretty cool to add them there, even if we have to go down to large stems only...
This is non-trivial since only the large stems have C fraction data. Slice 1: Include all traits except C fractions as predictors plus size, using as many samples as possible Slice 2: Include all traits as predictors, exclude small stems for which there is no C fraction data