I intend to compose proper posts when I have time, but I'll just drop some links and sketch some arcs for now.

Jeremy points to More than you’ve ever wanted to know about bison, which says in part that:

When the first humans began arriving in North America, these vast swaths of land were forested. No one is certain about what really happened. (There are many untestable but entertaining theories, of course, such as this Cheyenne legend describing the origin of the buffalo. On the other hand, the bisons themselves may be the ones to tell the true story... their teeth recorded millennia of changes in climate, through the different grasses they chewed.) In any case, the climate warmed; the trees disappeared, with the exception of riparian corridors; the Mammuthus primigenius and the Bison antiquus went extinct; Bison bison arrived; humans arrived, hunted, built tools, and used fire.

Perhaps not:

Another example of false narrative driven by urban myth involves the great plains of the Americas. The dominant deforestation narrative is that the plains were once forested in the ice age and post ice age period before humans arrived, and that humans burned them down to make a hunting park. The prairie and bison biome Eurasians saw when they arrived was a created environment.

This view was supported by analysis of lake sediments that showed large quantities of pine pollen from that era. The deforestation myth was supported. But there was too much pine pollen, a greater percentage than we find in a real pine forest since there are other forest floor species that contribute pollen too. This was ignored since the dominant deforestation narrative was served, just as the data from Guinea was ignored about that biome.

Later work grappled with the broken data, trying to answer the open questions, and found that pine pollen persists well due to a waxy coating while pollen from grasses and forbs does not. Digging in unweathered places revealed that there were few pine trees and that the great plains was a sagebrush grassland in ice age times. The prairie evolved from that grassland, and though there are different species now they are similar grassland species.

Which relates to "Can’t See the Forest for the Trees"

Despite assumptions that globalization is destroying forests, these researchers argue that in many parts of the world globalization and the policies that go along with it are in fact helping to create them. Migration from rural areas to cities or other countries, new markets for forest commodities, and even war are helping in some places to bring trees back. In other places the demand for diverse and far-flung products like rubber, tea, and açaí fruit, for example, is transforming existing forests and the lives that depend on them, often in unexpected ways. Perhaps most surprisingly, archaeologists and ecologists have discovered growing evidence that many forests once considered pristine, including much of the Amazon, have long been marked by human activity.

It's not only that the deforestation narrative is challenged, it is also the what have been called pristine environments are actually cultural landscapes. It's not just the N. American plains that have been misunderstood, it is also S. America, Africa, and Australia. It's not just historical neeping since there is current development policy at stake.