I had to resort to using the red phone to try and find out an answer to my green flames. My friend and Prof John Neely is who I turn to when I have a head scratcher concerning a wood kiln. I fondly refer to John as the man with the ceramic brain.
Here is John's answer:
"Wish I had a good answer for you. About all I can offer is kind of a
round about take on the subject. You’ll remember from salt kilns that
sodium burns yellow - well, calcium is more orange, potassium burns
purple and boron blue or green. I don’t really know much about other
colors (except magnesium, which is white) but that is how miners used to
analyze the rocks they were dealing with. A “flame test" was the first
thing they tried. You also know that carbon burns yellow, orange or red,
depending on temperature. Pine usually is dirtier - meaning more carbon
which would look red or orange. My guess is these minerals are what
influence the flame color."
So to add to the mystery here is a picture of the ash from the firebox. I thought I was hallucinating but the ash was green. I asked Duncan and Cassara to confirm and it is indeed green. So this must back up the theory that it is the mineral content of the wood that is giving us green flamers. It seems that certain woods contain a significant amount of boron. Apple orchard farmers can have their soil tested for boron. There is more to know about this wood firing than I can fit into this life time. I think I'll come back smarter in the next life.