OVERALL PATTERNS: Total Trees,
Number of Species,
TOP TWENTY: Pine (%), Spruce (%), Fir (%), Oak (%), Maple (%), Douglas-Fir (%), Juniper (%),
Birch (%), Poplar (%), Hemlock (%), Arborvitae (%), Larch (%), Ash (%), Sweetgum (%), Hickory (%), Tuliptree (%), Beech (%), Elm (%), Tupelo (%), Cherry/Plum (%), all other (%)
TREES TREES TREES
Bill Rankin, 2016
click on any image to download high-res version (one pixel = 2 km)
It also turns out that nearly all existing tree-range maps were drawn in the 1960s and 1970s by one person — Elbert Little, Jr. — to show the "original" range, before European settlement. (Osage orange is the classic example of how misleading these maps can be.)
My maps show patterns that can't be seen with the usual blob maps. In addition to the absolute and relative distribution of the twenty most dominant tree types, I'm also showing higher-level patterns: species diversity, deciduosity, and non-American trees. The usual split between eastern and western forests is immediately apparent, but so is the less well-known wedge of deciduous trees, which stretches from the Great Plains savanna and Mississippi alluvial plain to the forests of southern New England.
I've also used this same data to find more personally meaningful regions as well.