How to Make Concrete Tree Rings

Why make "tree rings"? you ask.  As part of a landscape, a tree is a very special plant and to give it a more formal air and enhance it's place in the garden, a tree ring adds that touch of formality and "class" to the scene.  In addition, with this method, I am able to "label" the ring, or add personal touches and or tree names.  It's a fun project and I plan on making at least a few more for other trees I have or will obtain. 

To make the ring, we need a form in which to pour the concrete.  I decided a three foot or 36" ring would be adequate for my small trees so started by making a 36" circle out of cardboard.

The circle is divided into 6 equal parts so that there will be 6 blocks or pieces of concrete surrounding the tree.  Consult any geometry book or go on line and look up how to dissect the circle into 6 equal or almost equal parts. The pattern is one of these 6 equal sections.  This can be traced, or when laying out the circle, use your circle drawing tools to mark a separate piece of cardboard.  I wanted to make the segments 4.5 inches wide, so simply drew an inner circle 4.5 inches shorter than the large template.

The pattern is then placed on a piece of 2 x 8" lumber, centered between the edges and the pattern to cut is marked.  Leave several inches on each end so that the ends when cut off can be used as end caps for the concrete form.

The first step here is to cut the angle of both ends. I use the cut off miter saw for this step. The form is now cut on the band saw as shown.

What we end up with is the basic form of 4 pieces of wood that will have a  base, or bottom,  attached with drywall screws.

I wanted to give the segments some character, so made pieces of trim as shown...these are cut from soft pine lumber, marked with the same pattern, cut on the band saw and then attached with brads and glue.  After drying, I took a disc sander and tapered the trim pieces down towards  the center of the form.  Now we are ready to assemble the form.

The base is attached with screws and basically the form is done.  I have three different forms in total, so all pictures are not entirely representative through all stages. 

Here, the ready form is oiled with a coating of vegetable oil, and  I have lined this form with a piece of plastic from a shopping bag.  Cut out with the aid of the pattern, then glued into place with spray adhesive.  I was using old plywood for the base, and it tended to leave residue on some castings.  Hopefully, the plastic will prevent this.

Here, I have cut out some letters of eps foam  on my hotwire machine. For a complete tutorial on making letters from eps (styrofoam) go to www.instructables.com/id/Hotwire-magic-The-Art/ .  This picture shows the name of the plum tree: Prunus ceracifera.  The other pictures show another possibility:  make the message a memorial note.  A good way to remember someone or a pet, perhaps, is to plant a living memorial such as a tree, and placed their name on the tree ring.  These should last for a very long time.

Here, one segment has been filled and is actually ready to be removed.  I found that using bagged ready mix (I buy the 60lb. bags.) it takes 5, 14.5oz. cans of mix and about 2cups of water for each segment.  Try not to make the mix too soupy, rather have it be a stiff mix.  Then jiggle form in two directions, and tap on sides and bottom with a rubber mallet to shake loose any air bubbles.  Then let sit for at least 24 hrs.

The final step is to place ring around tree.  I think it adds a lot to the appearance of the garden and sets the tree off very nicely.  Thanks for reading my instructable.

Completed a second tree ring as shown. Thought I would share that with the community as well.