random forests classifier

[cuttlefishh]

Some examples to consider:

• EMPO categories -- How well can we predict the EMPO category at multiple levels? (Zech did this already)
• ENVO categories
• Soil geography -- Can we predict where a soil is from based on its microbiome? (need to control for soil type, pH, other confounding factors?) @gilbertjack ask about this.