The image gl-seamless-bark-01.jpg below is in the Public Domain. I improved the image quality and put it back in the Public Domain. It is free for any commercial or private use.
You can right click the image above and save it to your computer.
This is a seamless tree’s bark texture generated using several photo manipulation techniques based on the PD texture I found here. The result image is small, but the quality is good enough to use for rendering 3D trees, rocks and rough surfaces. I made it seamless, heavily modified and put it back in the Public Domain, you are free to use it in your private or commercial projects.
File Name: gl-seamless-bark-01.jpg
Image Dimension: 512 x 512 pixels
File Type: JPEG (75% quality)
File Size: 92 KB
Samples of the render results: