POPSCI.COM / WINTER 2020 89Sanger investi-
gates spores on a fern that resides halfway up the Oregon spruce’s trunk, where light breaks through the canopy. Nearer the bottom, the darkness and damp help vines and other plants like the salmon berry flourish. In the tree’s most exCLIMBINGGARDEN posed upper regions, lichens and moss thrive in the brutal wind and sunlight; those organisms hold moisture from the air around their roots far from the forest floor.