A young spruce tree falls from the riverbank into a crook in the Roaring Fork River, still green with needles. Over time, I’ve watched its needles brown and thin. Eventually, bark and branches will fall off or be stripped by weather and current. Its trunk will finally settle onto the channel’s stony floor slowly, possibly over many years.

This river originates beneath the nearby crest of the Sawatch Range of central Colorado’s Rocky Mountains. Eighteen thousand years ago, glaciers swept down from the surrounding mountains, widening and deepening the river valley and polishing the bedrock. Today, its path carves through billion-year-old Precambrian granite, beginning at the outflow of Independence Lake and coursing 70 miles northwest to the mile-high town of Glenwood Springs.

During the winter, the river and downed spruce become encased in ice beneath deep layers of snow. During the spring, snowmelt swells the river and hastens its course through this otherwise slow, level stretch. The stream subsides during the summer and fall until its movement becomes barely perceptible. The tree’s fibers dissolve and eventually disintegrate through the annual cycle of seasons, its nutrients feeding life within the river.

- James Baker