Park

These are the only 'nature' shots I got from the park today.

Are those track marks from some bug in the bark?

You got it! Some type of beetle I believe.

We have something similar here. We have trees called 'Scribbly Bark' which are a type of Eucalypt. Australia is covered in Eucalypt's (Gum Trees) which explains the fierce forest fires we get. The eucalyptus oil in the trees burns very well.
Anyway, the trunks of the Scribbly Bark look like a kid has scribbled on them. It looks more like that than the definitive patterns you have captured there.