Figure 9 in Experimental induction of resins as a tool to understand variability in ambers

Figure 9. Multivariate analysis of Wollemia resin spectra using FTIR-ATR spectroscopy: (a) principal component analysis showing PC1 vs. PC2 – 3 indicates the three branch samples that came from different heights on the same tree (tree 3), and 1 indicates the four insect samples that came from different heights on the same tree (tree 1); (b) loadings for PC1; (c) cluster analysis.