Since i'm Swedish,....
Ponsse is from Finland.
Here this type of forest work is similar to farming just a bit slower, you harvest what your father planted and you will plant for your descendants.
1) What does the rest of the machine look like?
Assuming that the rest of the machine is the same as the cutter, ( sometimes these guys use a competitor harvester head)
2) What radio station is that operator listening to?
Don't know the radio station, but the song is Swedish https://www.youtube.com/watch?v=af4QsGb0eu0
3) How often do they need to sharpen the chain saw?
- Don't know.
4) What type of cutter is being used to clear the branches?
The ones i have seen are "knifes".
see the ponsse site ( above) look for "harvester-heads"