Unusual Spalted Birch Root Slab

I live on the north shore of Lake Superior where there are many large birch trees. I selected an old tree with protruding roots with the intention of cutting a slab just above the ground. The blue box in the image below shows the approximate outline of an 8" thick slab I cut from a similar birch tree. The tree I used was about 20" in diameter and of course the entire tree had to be taken down. The tree was dying. My goal was to make a bowl from the slab. Birch rots quickly so I hoped to catch spalting without too much decay. This image is of a different but similar birch tree. I of course failed to take a photo of the actual tree used.

The following images show the actual slab just before turning. There is a hole in the bottom of the root ball and decay is starting. I screwed on a plywood patch so the face plate could be securely attached.

Cross Section of Birch Slab

Birch Root Slab on the Lathe

Birch Root Slab on Lathe

The above images show the 8" thick root slab attached to my Stubby 1000 lathe using a 6" diameter face plate. I used a rotating center in the tail stock to stabilize this large piece as it spins. The turning went well but the wood was very spalted requiring repeated treatment with penetrating epoxy resin during the hollowing of the bowl. The punky wood had a lot of tear out so the epoxy was used to harden and stabilize it. This was a tedious process since the epoxy takes overnight to harden and three cycles of turning/treatment were needed on the inside and one on the bottom of the bowl.

The following images show the turned, dried (3 months), and sanded (to 400 grit) bowl after several applications of pure tung oil. The bowl is 23" in diameter and 5.5" deep. The bowl sanded smooth (like glass) with no signs of roughness or tear out.

Spalted Birch Root Ball Bowl

Spalted Birch Root Ball Bowl

This large bowl has beautiful spalting patterns and colors. The "wings" of the bowl show the protruding roots. This is best visualized in the images showing the bowl inverted. The bottom of the bowl is pointing in the direction of the top of the tree. The top of the bowl is pointing toward the roots of the tree. This bowl reveals some of the internal beauty of this tree just before the onset of decay.

This bowl was on display for the past 6 months at of the Hanifl Nature Center Exhibit at the Minnesota Zoo. The theme of the exhibit was "Art is an avenue to connect to and explore nature. Trees can inspire artistic expression. Trees are diverse, complex, and beautiful. Artists can be inspired by trees in many different ways." Trees certainly have inspired my art.