Question
how long does it take for a 60' pine tree to die after cutting holes in the truck at a 45* angle and filling with roundup concentrate?

Answer
That will more than likely not kill the tree. The living area of a tree is just under the bark so drilling into the wood and filling this with Roundup will only kill a very small part of the living cells.I would suggest that you cut into the bark all the way around the tree and fill this cut with Roundup. Make the cut about 1-2 inches wide and leave bark sticking up on the down side and paint Roundup from the container into the cut. This will kill the tree --it should show signs of dying in a week--needles turning red or brown. OF course you then will need to do something with the standing dead tree unless if it falls on its own it will not hit anything.