Dual Personality - poplar bark

Walking the Walton Road yesterday, I glanced into the woods and noticed several Quaking Aspens (Populus tremuloides) sporting their bark-of-two-natures. While the upper branches of most trees retain some of their younger, smoother features I can't think of another that displays young and old on the main trunk the way that poplar does.

As a young tree, poplar bark is grayish green with lenticels and markings similar to gray or paper birch. The greenish tinge is chlorophyll in its photosynthetic bark, capturing early sunshine in this pioneer species.

As poplar matures, the lower trunk develops stretch marks similar to northern red oak but without the reddish furrows. This is the stage at which many folks, myself included, can at eye level think that it's an oak.

Years later, the furrows lie between chunky ridges. The Maine Master Naturalist Program requires its students to choose a delimited site where we make regular observations. I had chosen a hollowed out piece of bark that turned out to be Big-toothed Aspen (P. grandidentata). As I watched activity around my delimited hollow stump, I noticed other  Big-toothed Aspens that had also dropped out of the canopy, a natural fate when these shade intolerant species are canopied by other species. Over time I became well acquainted with poplar's chunkiness topped by its smoother surface, a characteristic of both these poplar species.