Much of our national forests are choked with chemise and conifer seedlings, and little natural forest really exists these days.
Only that part that is privately owned bears any resemblence to a real forest.
After 10,000 years of aboriginal management, the term, "natural forest" is a myth. The reason they aren't the same is because humans aren't harvesting pine nuts, coppicing gooseberries, and killing both herbivores and competing predators. We need to learn how to run them differently, but doing that while retaining the early successional species that give restart its microbial life will take time and experimentation, not "preservation." This is to say nothing of the influence of exotics.