acurding from my observation and experience, it defend always on the situation special on the tree for an instance if the tree is young and only 3/4" in diagonal in thickness i sudjest to do the two process at the same time but make sure that the tree is healthy enough for the repoting becouse if you cut the roots specialy during sammer the amount of water for the tree is lessen and if or more leaves the more water to loss due to evaporation but if the trank is bigger enough you can make the prunning later. The porpose of this technique is to prevent the tree from drying out.
About the word "shuck" dont worry about that, thats a good sign specialy during replanting cause the tree is depending it self from drying out and if the plant loss its leaves naturally the plant itself will produce much more leaves in return when the times comes.