Spalted maple:

Ambrosia Maple:

Spalted maple comes from the wood essentially rotting. Fungi grow on dead trees and change the color.
http://en.wikipedia.org/wiki/Spalting

Ambrosia maple is caused by beetles that eat their way into the wood, bringing fungus in which changes it. Typically it's striped rather than the crackling effect like spalting.

http://www.wood-database.com/lumber-identification/hardwoods/ambrosia-maple/

 

When I made these bowls I assumed it was spalded maple because I never heard of ambrosia maple. Which do you think this is? Or something else. There are no bug or worm holes in it.

 

It is possible it could be both. The tree could have been infected with the beetles and after it died developed the fungus that causes the wood to be spalted.

 

Steve, I agree that both can happen in the same tree but I'm not sure what you are referring to in this sentence. Spalting happens when the trees is dead but does not require beetles and ambrosia stain requires beetles but only happens when the tree is living and the sap is flowing. That's why you see the ambrosia stain as streaks going up/down from the beetle hole.

Tewitt, I think that particular piece only has ambrosia stain but I can't see the bottom clearly enough to tell whether or not it has a little spalting as well.

The two are shown clearly on my site (which is where jmartel got those pics).

 

I collected about 20 logs during the summer to cut for fire wood in the fall. Since they were all in a large pile, I'm not sure if it had been a living tree of dead or even on the ground. I only kept about 6 feet of it just to see what it would look like after turning. I do have some of the original 20 logs that never got cut, but not sure if any of the sample log is left. It may have gotten split for fire wood.