looks like a lot of separate trees and doesn't look particularly old, but they're all part of a single entity called a clonal colony of a single male quaking aspen in Utah, and it's the root system they share that is estimated to be about 80,000 years old. Its status as a single entity is determined by DNA. And there are probably a few somewhere in the world even larger yet to be discovered and hopefully not destroyed. I don't recall its ever being mentioned on Trek, although it certainly seems worthy. When I see the listed dimensions and mass of a Federation starship, I think of Pando, which is much larger yet with much lower estimated mass. Supposedly starships in coming centuries will be made largely of graphene, which is 200 times as strong as steel by weight. But already carbon-fiber automobile body panels are much lighter than their steel counterparts, although so far much more expensive.