If you don't cut them down the first year, they become decent sized trees. However, it isn't about total individual tree size. It is about the fact that they tr

If you don't cut them down the first year, they become decent sized trees. However, it isn't about total individual tree size. It is about the fact that they trap more carbon into wood tissue per year, because they grow so very quickly. An oak may take 20-50 years to reach the size an empress tree will reach in say, 5-10 years. Therefore an oak traps carbon far more slowly. Oak is stronger, nicer, harder wood, because it grows more slowly, but also captures carbon more slowly. Different growth habits, different speed, from different ecosystems, with different uses.