I am removing the punky exterior casing trim and part of the sill of a window that a woodpecker attacked.
There is a vertical piece of wood about 3/4 x 1 on left and right partially below the casing trim:
I've removed the trim and those two pieces. Here's the one from the right side of the window; you can see the white primer which was hidden behind the casing trim and not painted:
These two vertical pieces have a small channel routed into their inside face.
I need to replace those pieces because they're punky near the sill and the woodpecker destroyed the bottom section of the one on the right side of the window. Is that channel on the back side to let moisture drip down to the sill?
Here's a picture of the window with the casing trim and that strip of wood removed:
The top of the groove would be right where the mitered-corner of the casing trim would channel water.