I like trees and so I appreciated the trees in the gardens at the Baths of Caracalla. Roman stone pines (or umbrella pines) are particularly impressive and lend themselves well to shading ground well below. The big trees have orange bark, while the younger ones seem to have darker bark. I cannot find references to this. I do know that ponderosa pines have a characteristic of darker bark until they are about a century old and then it turns orange, but I did learn that stone pines do not live very long (for trees) rarely more than 150 years. So, who knows?
Stone pines probably originated on the Iberian peninsula and were localized there, but Romans and other ancient people planted them all around the Mediterranean, and they are now naturalized in most places where the Romans once ruled.
Notice in the last photos the one pine is yellowing up top. They need more for the next generation.