Clearly, the only correct solution is to wrap the tape measure around the branch in a spiral pattern, all the way down the length, as that covers both options.
The width is what gets you odd looks while attempting to put that branch into a wood chipper the length or either measure can be helped by trimming it down, or placing the chocks around the base so it doesn't go all the way in. Using grease to coat that branch and attempting to adjust the chipper entrance can be very difficult unless you have a crow bar or a spreader.
I'd say the top method because, if you cut it, you are not going to cut at an angle. If you make something out of it, you are going to cut it straight across and measure its length from the cut end.
Assuming the branch is flexible (for some odd reason), you push it down just enough for top and bottom to even out and then it doesn’t matter which side you measure on ;)
3rd option grab the dick stretch it out and then let it go. This is more for fun not for measurement. then yell out "Sorry wittle guy!" yes "wittle" its sounds funnier than little