Anywhere from a few days to a week or more depending on conditions & manpower available. They had to cut above the root structure, so that meant climbing up & notching the tree on opposite sides to install buckboards to stand on while working the saw. Just that might take part of one day. After it was fallen you had to cut the tree to lengths to be able to move it after that, so it was a very slow process. Fortunately, they didn’t get them all.