Hi and welcome
Pictures would help us a lot to help you out here. If you can show both trees in one picture, plus a closer picture of the light green one that would be great.
It's most likely to be a difference in the soil pH causing the yellowish tree to become nutrient deficient. Is it closer to a concrete structure of some type, like a driveway or a sidewalk? The leachings from concrete can drastically affect the soil pH. That's the best I can think of off the top of my head. Please post some pictures!