Don Stephan
Perhaps 10 years ago I spent an hour on the internet reading everything I could find on red box elder. One find was a research paper that concluded after a series of experiments that the red color was due to injury or other insult to the wood and not to fungi. I also found a comment that a woodturner had asked his neighbor research chemist to analyze the red color. The chemist said it was a type of relatively unstable molecule that would be degraded by UV light. A quick search just now did not find the research paper or the comment.