The large trees were the norm, although by 1820 there would have been plenty of poles coming in. However it had nothing whatsoever to do with lack of a logging indstry. As Shgnasty already noted, it was due to Indian environmental destruction. The Indians deliberately set fires to destroy the forest and create a savanna parkland. Fires can easily kill small treees, but large trees are much more resilient. As a result the mortality curve for trees in Indian lands was very odd, with >99% mortality for the first ~20 years of life, then <1% mortality for the next 200 years and then a gradually increasing chance of mortality with sensescence.
What that all meant was that in Indian parklands theer was almost nothing but big trees. There would have been a tiny number of saplings and poles that had managed to survive the fires, but because large trees supress small tress and prevent them form outgrowing the flames probably less than one in every 100 trees would have been less than 75% maximum size.
Probably not. Size is a really lousy surrogate for age in trees, if you can’t control for all environmental factors it’s little better than making a random guess.
The thing about trees is that they supress other trees. When trees are allowed to grow in a parkland environment such as that maintained by the Indians they are so widely spaced that they don’t compete much for light or for water. That means that each individual tree can harvest maximal resources and reach maximal size.
In contrast in a natural forest each tree is competing with its neighbours for light and water. As a result no tree can reach anything like maximal size. This is no different to the situation where you raise large numbers of animals at high densities: while some indivdiuals may grow larger than others all are stunted due to starvation through competition.
So it’s very likely that those 24 inch trees you are seeing are the maximum achievable size in anatural forest. They may well be centuries old despite their small size.
In short, just because tree is small in anaturla forets doesn’t mean it is young. And just because trees were large in Indian parklands didn’t mean they were old. Size is a really lousy surrogate for age in trees.
The only place you are going to see large numbers of these huge trees are places where either regular burning has continued to the present day or where regular fires have never occured. Everywhere else in the world we’ve had a situation where fire supression has allowed approximately natural wooldans and forests to reclaim the land cleared by indigenous peoples.
You might be thinking that shouldn’t remove all the big old trees that were there cnbturies ago, but it does. Large trees have much higher water demands than small trees, and when small trees encroach onto these giants the amount of available water decreases and the big old trees die in any droughts.
It’s normal to think of the current forest as being somehow inpoverished and unnatural, and the Indian parklands as being natural and diverse, but the truth is that we probably have more forest approximating a natural state in the US today than at any time on the in past 5, 000 years. tehre have also been serious estimates that indicate we have more individual trees. While the Indian parklands with their huge old trees must have looked impressive and been a hunter’s paradise they were every bit as unnatural as a ploughed field or a sheep pasture and probably of no more value from a biodiveristy POV.