I have always loved the bark on the Ponderosa pines. It has great texture and the pieces that slough off look like puzzle pieces. Needless to say, I have a collection of those.
Here’s a photo of the Ponderosa pine bark. Not only great texture, but interesting colors and shapes.
Here’s a photo of the resulting applique I created based on bark. I used a felt background with inclusions to give more volume to the raised areas. I then added a variety of silk applique and stitched down with hand dyed wool thread in a variety of colors. I then machine stitched the background to flatten those areas and give the piece more depth.