Basic Divisions (for Aesthetic Considerations) Among Trees

Dichotomies:

1. Evergreen vs. deciduous
2. Conifer vs. broadleaf
3. Rounded vs. pyramidal
4. Leaves simple vs. compound
5. Northern hemisphere vs. Southern Hemisphere
6. Western Hemisphere vs. Eastern Hemisphere

Usually three elements go together, i.e. evergreen, pyramidal conifers vs. deciduous, rounded, broadleaf

But by no means always.  There are: 

1. Deciduous conifers (always pyramidal?)
2. Rounded conifers (always evergreen?)

“Multichotomies”:

1. Taller than wide to tall as wide to wider than tall (rare)
2. Tall to medium to short
3. Fast to medium to slow
4. Dense to medium to open
5. Tropical to semi-hardy to hardy
6. Leaves big to medium to small
7. Hydrophytic to medium to xerophytic
8. Low pH to neutral to high pH
9. Low elevation to mid elevation to high elevation
10. Flowering/fruiting/fall color values high to marginal to zero
11. Long-lived to medium to short-lived
12. Taxonomic group (major) e.g.:  Myrtaceae, Fabaceae, palms, oaks, pines, bamboos . . .
13. Geographic group (major) e.g.:  Mediterranean, Californian, Australian, South African, Japan/China
14. Obligate tree to versatile to obligate shrub
15. Weedy to easy culture/non-weedy to difficult
16. Full sun to versatile, or filtered sun to shade (rare)