I have an answer for Amur maples. Last year I posted, asking why some amur maples
(acer ginnala) were not red or crimson but instead were yellow for Fall color.
Whether it was a genetic problem or a climate weather problem.

What I did last year was cut every amur maple that was yellowish down to the ground.
They came back but are much smaller trees than the red ones.

This year, all of my Amur maples, even the yellow cut back ones of last year, are
flaming red or crimson. A few have a touch of yellow.

So it looks as though the answer is that the color is dependent on yearly
environment conditions. And that I needlessly cut back the amur maples. So I guess
genetically all amur maples have the potential of crimson red color but that the
environment circumstances for that year will determine the color of the Autumn
leaves.

P.S. a sidenote. I have found that my currants give me as much color as the amur
maples plus the fact that the currants give me beautiful fruit for the summer. And
so I should have planted more currants rather than amur maples. So often we worry
about some minor details of things when the best answer is a whole new and different
other category. Another example is that I bought apple varieties that were resistant
to fireblight and where the problem now arises of apple-cedar-rust.
If I had simply instead gone around to the apple trees in the area that had done the
best and grafted those trees, I would probably have been better off.

Archimedes Plutonium,
whole entire Universe is just one big atom where dots
of the electron-dot-cloud are galaxies