Into the Sky Garden

By Alexander Smith

As another early spring windstorm sweeps through Wildwood, I take my routine walk along the paths and creeks to check for fallen trees. Much as I had suspected, on the banks of our lower forested wetland, a large Douglas-fir—a towering giant that had stood for centuries—has toppled. Walking its length, I reach its crown, where a magical kingdom has emerged. At ground level, I am struck by the vibrant contrast between the tree’s bark and the lush life now coating its branches. Mosses, ferns, and lichens cover the limbs, creating a self-sustaining world high above the earth—a sky garden, vibrant and teeming with life.

In the Coastal Douglas-fir ecosystem, towering, centuries-old trees are more than just the foundation of the forest; they support hidden ecosystems in their treetops. These sky gardens, teeming with mosses, lichens, ferns, and decaying plant matter, are rare, found only in well-established old-growth forests. They take centuries to develop, offering shelter and food to a wide variety of species, from seabirds to squirrels. Despite their importance, sky gardens remain little understood, often only revealed when the host tree is felled. This lack of recognition has hindered our understanding of their ecological value and prevented effective conservation efforts.

Old-growth trees like this Douglas-fir are uniquely suited to support sky gardens due to their immense size, age, and structural complexity. Unlike younger trees with thin branches that shed debris, ancient trees grow massive limbs that act as platforms for plant life. These branches collect fallen needles, bark, and decaying leaves, creating pockets of canopy soil—a rare phenomenon where organic material accumulates in the treetops, mimicking forest-floor conditions. This accumulation creates a nutrient-rich environment where mosses like Oregon beaked moss, ragged-moss, and electrified cat’s-tail moss thrive. Over time, branches become coated in spongy layers of plant life, forming a self-sustaining ecosystem high above the ground.

One of the most fascinating species to rely on these sky gardens is the Marbled Murrelet, a seabird that nests exclusively in the canopy of old-growth trees. Unlike most birds, murrelets lay a single egg directly onto thick moss mats in the treetops. These elevated nurseries provide insulation and camouflage, protecting the egg from predators like ravens and owls. Unfortunately, widespread logging of old-growth forests has limited the murrelet’s nesting habitat, causing its population to decline. Since sky gardens take centuries to develop, younger forests cannot replicate these conditions, making conservation efforts even more critical.

Sky gardens also support a thriving population of insects and invertebrates, such as beetles, spiders, and springtails, which form the foundation of the food web. These tiny creatures feed birds, bats, and other canopy-dwelling animals, further enriching these ecosystems.

At Wildwood, our practice of ecoforestry and selective logging helps maintain the complexity of sky gardens. By carefully removing select trees and allowing others to grow old, we preserve these treetop ecosystems. This approach ensures that these fragile habitats continue to thrive while promoting forest health and biodiversity. Protecting sky gardens depends on balancing human activity with the preservation of old-growth forests, which we strive to uphold with every step of our stewardship.

Sky gardens are more than just collections of moss and ferns—they are living islands suspended in the heights of ancient trees. Their survival depends on the protection of old-growth forests, ensuring that these treetop communities endure for generations to come.