Grievous girdles galore

That looks like a girdle mark.

The next tree has been girdled so badly that a side branch took over as the leader.

Another.

This one lost the main trunk from girdling and sprouted two side branches into competing leaders.

Here's one with a visible cause for its girdle.  Most of the time girdles are caused by well-intentioned support ties, just like this.

Another stuck in place.

A close up showing that the girdle formed from tubing-wrapped wire used to support the tree when it was just a sapling.  Support materials should be flexible - I commonly see a tough-looking rubber band or inner tube type of material that seems about right.  Two support poles should be placed on opposite sides of the sapling and the support should be loose enough to allow the sapling to move in the wind.  Don't support your trees with wire, even if it's wrapped with tubing and don't leave the support in place long past the time its needed.  Unfortunately, these trees have been weakened and diminished aesthetically by their girdles.