This probably represents a division that is too fine for Tennessee using these variables, the ideal being somewhere between 13 and 17 divisions. We can subject a 5 state area to the clustering procedure using the same variables to produce large-scale regional patterns of plant growth. There are 15 MLRA regions in this area . In addition to the Tennessee MLRAs, we see the Fall Line, the Coastal Plain, and the Piedmont in the south, and Pennyroyal Plain in Kentucky. At 10 clusters , the division of the 5-state region is too coarse.
Some clusters occur in more than one region of the map.
This is the 5 state area clustered into 15 ecoregions , the level of division of the MLRAs within this region. But the clusters are very large. 20 ecoregions reduce the average size of the clusters considerably. This is 25 clusters . Now we can see all of the major divisions in Tennessee, and the Smokies stand out quite strongly.