This is a very hard sum, worked out for Heather, who commented on the fact that I should not ask questions about woodchucks and their work ratio with out the backup of advanced mathematics.
Well, I've got the measure of you, lady, with your fancy ways! So, here is a very hard sum. I have calculated that 612 over 35-7 for the thing, needs to be timesed by a 4% drop in activity on a 16min tea break. Then times by a 124 degree beak ratio over a wide angle of 631.444 doobreys, divide by Widdy, and add the number of wankel rotary engines in a seven mile radius over a log pile of 619.
The result is: A woodchuck can clear 6 logs, 4 twigs, and clear 2 piles of leaf litter when he's almost finished.
(And yes, I have shown my workings!!! :-P)