"Three hundred years ago, the Appalachians were covered with very tall trees"
Actually, there were significantly large areas such as the Shenandoah Valley, and the Barrens of Kentucky which had been burned out by the Indians and were maintained in a grassland state as a Buffalo common for all to hunt on. Don't know what changes there were as a result of European settlers, except that they killed off the buffalo.
Regarding the common age of 50 thousand years ago (kya) as a possible age for the Topper Site, and the Australian settlement.
Around 74 kya, the great Toba Caldera was formed by a gigantic volcanic eruption (18 miles by 65 miles in diameter). Scientists now believe that human kind was reduced to no more than 5 or 10,000 individuals. There was also a significant worsening of the ice age. Then around 50 kya we begin to find significant traces of a resurgent human population. It therefore makes sense that human remains would start to show up in many places again after all that time. My question: What will they find if they start looking to before 74 kya for remains?
Regarding scientific orthodoxy: Yes, the attitude of nothing before Clovis was widely held and dissent was strongly discouraged. No grant money? This was the same attitude held by the archeology establishment regarding undersea archeology, despite the fact that most major settlements are built near the ocean or where rivers enter the sea. Since sea levels for much of the past 100 ky was 300-400 feet lower than it is now, it stands to reason there must be interesting things there. Graham Hancock has spearheaded inquiries in this direction. Now all kinds of research is being done along various coast lines. Can't wait to see what the next 10 years dredges up.