I heard this today on a talk-radio show about gardening.

Problem:
The preposition should not appear in this expression.

Explanation:
The caller who said this was describing a location on her tree to the gardening-show host.

That point on the tree had a scar.

The caller made the common English blunder of applying “where at” — a mistaken way to use “where” — to the location of the tree’s scar.

What’s ironic is that the lady probably thought that “at” helped to clarify or emphasize “where” but instead confused many listeners because “scar at” ran together as “scarrat” — resulting in “… where it has a scarrat now” — leaving us wondering what a “scarrat” was.

Solution:
“… where it has a scar now.”