This looks like a striped maple (Acer pensylvanicum). It's a common understory species in New York, it thrives in the shade (as it would under the spruces you saw) and can be found in large numbers in some areas. It usually reaches 20-40 feet in height, and sometimes up to 6" in diameter or more. The pattern of bark is always the same, but the color does vary. Most are lush green, but some can show brown, red, or even the bluish color you saw. Personally, I think I've seen a pattern where the non-green colors are more prevalent in the winter. But I don't have proof of this. It is just my observation.

Agreed on this as striped maple. I appreciate you sharing your sense that the green colors are less prevalent in winter. While most trees conduct photosynthesis in just the leaves or needles... there are some trees that also have chlorophyll present in their bark (most notably quaking aspen). I'm not aware of research confirming this for striped maple, but it would make sense. If you grow in densely shaded conditions, it makes sense that you would take advantage of food production across as much surface area as possible.