Moose chew bark off of the trunks of trees, especially Populus tremuloides. See some of the following examples:
- iNat 114539470
- iNat 114539399
- iNat 114538848
- iNat 114538783
- iNat 114538569
- iNat 114538481
- iNat 114538387
- iNat 114538247
- iNat 114537633
- iNat 115635455
Often the teeth marks are at a diagonal, which could be quantified with an inclinometer. In my imagination I see them applying most of the force downward with their top jaw teeth. I also suspect that for higher up parts of a trunk that are chewed that the inclinometer angle would be steeper due to the moose reaching up at a more acute angle with respect to the trunk. This could be confirmed quantitatively by measuring the height of the chewing from the ground and comparing to the chew angles at each recorded height.
The markings may depend on the type of tree. The examples given above are all on aspen trees and show lots of teeth marks, but this video Moose eating bark shows a moose both chewing and pulling in order to get bark off a maple tree. The iNaturalist observations from above are from a similar area, but this video Moose Eat Poplar Tree Bark is unlikely to be from the same area but also shows lots of teeth marks.
Can we estimate the approximate orientation of the head of the moose relative to the tree trunk based on the chewing marks?
Note: This video How Humans Became (Mostly) Right-Handed claims that some information can be inferred from scrapes on surfaces. However, this considered scratches on teeth by (presumably) tools rather than scrapes on trees from teeth. This comparison is only analogical because the reasoning and methods could be quite different.