Around here, trees age like this.... An oak tree sitting out in the middle of a field with no competition for sunlight will grow short and stout, like the FAT oaks you see along country roads next to fields. You put that same oak tree in a forest with other trees where it has to compete for sunlight, and it will grow tall and straight, but not nearly as FAT.
We have a section in our forest that we planted in 1989 with alternating rows of pines and mixed hardwoods. The pines grow fast to stress the hardwoods to reach for sunlight between them. Eventually, the hardwoods peak out over the pines and start putting on girth.
After 35 years, the largest hardwoods are only about 12-16" in diameter at chest height in that section.