Tree Species - Appalachian vs. European

[TriPolar]

@Colibri

Not much if any. Botany in North America dates back to the 1700s, and lots of North American species were included by Linnaeus in his Systema Naturae. In any case, there was much more splitting of taxa by early botanists than by 20th Century ones. I would expect that the present European and North America lists represent similar taxonomic philosophies. There is certainly not enough of a difference to account for the much higher diversity in North America.

Ah well, thanks. It was a shot in the dark. I don’t know how many species there are in the Smokies, but there’s certainly a lot of trees.

[Spoke]

I think Colibri already alluded to this, but isn’t it generally accepted (Colibri’s contrarian link notwithstanding) that the diversity of the Appalachians is owing to their generally North-South orientation (as opposed to the general East-West orientation of the Alps and Pyrenees)?

When the glaciers advanced and retreated in North America, species were able to migrate northward and southward along the valleys of the Appalachians with the changing climate. And as the temperatures warmed, relic populations of cold-weather species were left behind in the higher elevations of the Appalachians. In North America, species had the possibility of retreating all the way into Florida as temperatures cooled, and then returning northward as temperatures warmed.

In Europe, on the other hand, any species north of the mountains and not able to adapt to the cold would have been wiped out (or scoured away) as the glaciers advanced.

[Colibri]

@Spoke

I think Colibri already alluded to this, but isn’t it generally accepted (Colibri’s contrarian link notwithstanding) that the diversity of the Appalachians is owing to their generally North-South orientation (as opposed to the general East-West orientation of the Alps and Pyrenees)?

When the glaciers advanced and retreated in North America, species were able to migrate northward and southward along the valleys of the Appalachians with the changing climate. And as the temperatures warmed, relic populations of cold-weather species were left behind in the higher elevations of the Appalachians. In North America, species had the possibility of retreating all the way into Florida as temperatures cooled, and then returning northward as temperatures warmed.

In Europe, on the other hand, any species north of the mountains and not able to adapt to the cold would have been wiped out (or scoured away) as the glaciers advanced.

Yes, that’s the conventional explanation, not just for trees but for other groups of organisms in Euroep. Likewise in eastern Asia trees were able to migrate south into southeast Asia.