"You are the one doing the assuming here. I take care of the grounds of a college, which means both gardening and cleaning up after students. I can tell you, without assuming anything that oranges take a long time to breakdown, banana peels turn dark within a week, shrivel up and hang around till the rains, cigarette butts lose the paper in a few weeks and the filter stays, kleenex only needs to get wet a couple of times before it leaves a hundred small specs of paper that will be dispersed with a couple of kicks. And so on and so forth. Science is it as far as I am concerned, but I don't need it for this. I know firsthand."
A big +1 As a long time serious gardener, I can second Katharina's remarks. Also, as I have posted elsewhere, I have personally inspected numerous sites where I made my deposits a year earlier under half buried small boulders at altitudes of 10,500-11,000' in the Sierra and found nothing identifiable as fecal matter or TP. I do not draw conclusions about other areas from my experience there because the rate at which organic matter decomposes varies wildly in relation to its carbon/nitrogen content, moisture levels, soil porosity(oxygen availability), and temperature, to name the most critical factors affecting the process. I would caution those of you who quote scientific studies based on a limited number of sites or operate on nothing more than your reactions to disgusting examples of poor backcountry poo practice to think the whole issue thru carefully before issuing blanket condemnations
and preaching that there is but one acceptable way to deal with poo in the backcounty. If you choose to pack out your used TP, fine, but do not assume that is the only acceptable way to handle the issue.
As for animals digging up the buried TP/poo, I have yet to find an example of that in situations where the deposit is made in the hole left by prising a half buried boulder aside and re-setting it in its original position after I am done. And I have been doing it for nearly 40 years now, which means the animals have had a lot of opportunities. You would also be hard pressed to detect a boulder I have used even an hour later. I am meticulous about restoring the duff around it. A little humility and tolerance. Please.