Snags, also known as wildlife trees, are an essential part of our ecosystem, making up 10-20% of the trees in the understory, the layer beneath the canopy in our forests.

Have you ever walked through a forest and stopped to notice what was happening in it? Besides the layers of beautifully lush green flora and fauna, have you observed the coarse, decomposing standing broken trees and their fallen woody brethren on the ground? I once thought of these decaying trees as debris, imagining a stack of natural Jenga blocks scattered and abandoned throughout the forest by an oversized child. While funny to think about, I know these trees were felled by an essential part of the forest lifecycle: by natural disturbances like high winds, microbursts, tornadoes, hurricanes, wildfires, ice storms, and disease. The decomposing standing trees appear artfully strangled by Poison Ivy, Grape, and Bittersweet vines, and the fallen ones have commingled with leaf and needle litter, twigs, pine cones, tree nuts, boulders, and rocks. So much beauty, surrounded by so much decay and death – or is it?

The Appalachian-Northeast Mesic Forest in New York, the deciduous and mixed forests of Pennsylvania, and the Eastern Cascades in Washington have enchanted me since I was a little girl. These forests are filled with life, mystery, wonder, joy, beauty, enchantment, and fear of the unknown – or maybe ignorance – as I did not always know the full extent of the importance or value of our forests.

Snags play an important role in supporting life in the forest.

Snags resemble large jagged toothpicks that have been twisted or broken off, leaving sturdy standing stumps behind. They can remain in place for 2-10 years and sometimes longer, depending on the region in which they reside. Snags and downed decaying trees add structural diversity by nurturing life through nutrient-enriched decayed soil called humus. Lichen, moss, varieties of mushrooms, and mycelium, a fungus-like colony, branch out underground like a road map in all directions. Snags retain a lot of water, and the decomposing trees support plant growth by adding vital nutrients to the soil through the nitrogen cycle.

Forest Snags with Mushroom
In the forest’s understory, many beautiful varieties of ferns, wildflowers, shrubs, and tree seedlings grow close by.

Snags provide an essential food source and habitats for organisms, insects, amphibians, and reptiles. Cavities drilled by woodpeckers in snags create habitations for other birds, owls, and mammals such as mice, chipmunks, squirrels, and deer. Once a snag topples over and continues to decay near a water source such as a watershed, creek, or stream, the root system can help to hold soil in place, lessening soil erosion and stabilizing the banks of the water source. In the water, decomposing snags provide new life, habitats, protection, and food, such as algae and bacteria for aquatic animals, macro-invertebrates, and fish. According to the National Wildlife Federation, “Dead trees provide vital habitat for more than 1,000 species of wildlife nationwide.”

Oh, the stories trees can tell us if we only look and listen.

In many of the old-growth forests that I have been fortunate to have hiked through, I have found myself deep in thought, wondering about the variety of trees I beheld, estimating their age, and imagining what the trees have experienced and seen throughout history. I ponder the relevance of trees in our lives now in this ever-changing climate. I envision who may have camped or sat against these large trees, the historical events they might have lived through, the romances that they witnessed, and how they came to be here. Is their existence thanks to man, an animal, or a bird? Or did a seed fall, reemerging as a seedling in the spring? There’s so much to marvel at when walking through the forest.  

I no longer see snags as old dead, decaying trees but wonder at all the life they support. Peter Wohlleben writes in The Hidden Life of Trees, “But we shouldn’t be concerned about trees purely for material reasons; we should care about them because of the little puzzles and wonders they present us with.” Read our summary here.

Written by Yvonne Dwyer

Written by Yvonne Dwyer

Master Naturalist and OPL Content Contributor

“It is truly an honor for me to be a contributor to One Planet Life. By sharing my experiences and lifetime of learning, I hope to inspire conservation, sustainability, stewardship, and awareness of enjoying the natural wonders of the world for the wellbeing of people and the planet.”