Anyone know what this "Bearing Tree" sign means?

This stuff brings back memories. Back in the dark ages, I had to take surveying as a civil engineering student and had to pass both tests for my license. My final project was to recreate the boundary associated with a Spanish land grant in California. There's a process to do "closure", i.e. to make the ends meet. The tough one was "North to the Oak by the river", that didn't exist anymore, and the distance was "two smokes on a good horse". I figured it out by going both directions from a starting point and the registered surveyor signed off. Passing grade.