Can the autumn leaf color on a given tree vary from one autumn to the next?
Generally no, the color a tree’s leaves turn in the autumn is genetically determined. However there can be significant variation due to differences in light exposure, temperature, and water. For example, in the courtyard outside my office there are three essentially identical oak trees. However one is near the south wall (largely shaded), one near the north, and one near the east. One autumn recently, the three trees changes to three distinct colors; yellow, orange, and red. This website has more details. Q: Why does light produce color? A: Light produces color because of how our visual systems respond to light with different responses to the various colors in the spectrum. Without our visual system, light can’t make color on it’s own. Q: Why are leaves green? Why not black? A: Here is a website that explains why plants are green. It is interesting, but it really doesn’t address the question of why they aren’t black. One might think that black leaves would absorb even more sunlight and
