Great help
Yup, about as much as half of the thread.
I've worked on trails with masters of crosscuts. It's very interesting--there are a few specialized tools. I had never heard of an underbuck tool, but there is such a thing and I got to use it.
The first thing one does, after sizing up the tree, is to remove the bark where you will be cutting, and one guy had an old spud that he found in an antinque store on the east coast. Old tools still get used.
You can use an axe for the underbuck tool, but the same guy that had the spud had built one using aircraft metals to make it light weight. When you do trail work, you pack in so want tool that are as lightweight as possible.
They ground down plastic wedges as the kerf on a crosscut is narrower than a chain kerf.
Note the cut mentioned in the handout about not matching top and bottom cut so the log doesn't knock the saw out of your hands and squish the saw. It might come in handy on the tree shown in the picture.
It's all quite fascinating, although I found myself thinking how much faster a chainsaw is.