Any pics of this trail?
I am thinking that any trail you couldn't pull some kind of trailer through, and your ATV will barely make it through, won't be very safe to try with wood piled up on the racks.
A walking beam trailer is the answer for rough ground - but all trailer/tow vehicle combos do have their limits when it comes to hills & loss of traction. I have spun out a time or two with mine, with not much load on it - I have also been up on two wheels unexpectedly a time or two with not much weight on the racks. (I keep 2 saws, gas & oil on the front, and have a box/passenger seat on the back with all kinds of other stuff in it). If I was going to try wood on the racks, I would just solidly bolt a plastic tote on each rack, and start with small loads - at least the weight will gain you traction, and help keep the wheels on the ground going up & down hills, but the side to side pitches could bite you badly.