For this type of chair, the tree is cut at about the three foot level, and then the stump is cut flush with the ground. It is turned on its side and supported by rocks to protect it from rot. The seat cut is 10 degrees above level while the back is cut 100 degrees from the seat. I faced the surfaces with cedar fence boards overhanging the stump about one inch.

Shore Pine Chair

Douglas Fir Chair #2
also Alaska Cedar Chairs

The tree is cut two or more feet above the ground. Then the stump is cut at a 10 degree angle, with the back of the angle close to the ground. The removed piece then becomes the back. This piece can be recut to make it 100 degrees from the seat, or simply supported by rocks or cedar blocks to give the correct angle. In this set of two chairs with end tables, I also used three other pieces of the trunk.

The tree is cut to the desired height of the chair plus the height of the back.

 

White Fir Stump Chair
also Douglas Fir Chair #1 and #3
and Spruce Stump Chair

Using 8-inch lag bolts, the back of this bench was attached to the end of a 20-foot section trunk on an uprooted Port Orford Cedar. The seat was then lag-bolted to the back, with additional support from the arms and a steel rod underneath. The chain holds the chair down so the sitter is not catapulted across the garden from the weight of the massive roots.