So, to summarize, there's a wide variety of different chemicals plants use for photosynthesis that all look different colors to us, and we just see the reds and yellows because plants are sucking up chlorophyl to store in wood for winter?

And then late leaves look brown because the leaves lose these other chemicals? Do they also store these other chemicals in their trunks over winter?

If I recall correctly, this is why most of what we've seen beyond our galaxy is to galactic "north" or "south". If we aim our telescopes along the galactic plane, there's a ton of dust in the way (the "milky way" you can see with your eyes when in a dark enough location) that makes it hard to see anything past that.