The Understory and Its Emergence at 360 Trails

The sky may be gray and the tree limbs skeletal, here in late fall, but the forest understory is a riot of color. I cross a disco carpet of fallen willow leaves as I climb into 360 Trails, ready to explore.

I enter a mossy hollow full of tiny white mushrooms like hailstones. They’ll probably last about as long. The moss glows with health that commands attention as it vibrates with the cries of chickaree squirrels. Then comes the lonely, ghostly trill of a varied thrush.

In forestry, nearly all attention is given to the timber trees. How we understand a forest and its growth stages, health, management priorities, long-term sustainability, and climate resilience all revolve quite naturally around the forest’s dominant members.

Trees hold sway over conservation thinking too: think of the initiatives to plant millions of trees, to value the carbon captured in trees. And literature: in Annie Proulx’s “Barkskins” and the Pulitzer-winning Richard Powers epic “The Overstory,” it’s trees, their planting and cutting, their shade and wood and deep connective powers that give them a top-level influence on the plotline of civilization.

Wood is a big part of my own cultural DNA. But today I often forget to look up. 360 Trails is an excellent place to witness the emergence of forest understory and to contemplate its importance.

To a forester, there are four basic stages of forest succession. 360 Trails, owned for now by the Department of Natural Resources and managed for timber production, though Key Pen Parks has a 50-year lease for the trails and hopes to acquire the land outright, is at a fascinating ecological inflection point. A forestry definition of succession is “the change in the mix of tree species present in a stand over time.”

See the focus on trees?

First comes stand initiation. Sun-loving pioneer species like Douglas fir and red alder carpet the bare earth. Decades later comes the second stage, stem exclusion. The pioneer species have grown until they are packed like sardines. A good example is on the right as you head up the main hill to 360 Trails. The even-aged trees, suffering from insufficient girth and ripe for disease, have a dense canopy. The understory, starved of light, isn’t much more than sword fern. It’s a stage with little to offer to wildlife.

Traditional forest industry doesn’t mind: such trees are easy to process. Ecological forestry sees this as the stage where active management has the greatest impact. Thinning and the creation of gaps open the forest to the third stage, understory reinitiation, where shade-tolerant trees like red cedar and maple become established among a smaller number of now-healthy firs, and shrubs and small trees bring a rich mix of fruit and color and life into the forest again.

Big parts of 360 Trails are there now. (If allowed to age another 100-200 years, it will reach the final stage, old-growth ecosystem.) My long hike today is always among firs, but the mid-canopy trees shift and change — dogwood, willows, cascara, hazelnut.

Here is a strange, small tree arcing toward the trail. I examine its triple-pointed leaves. I know these leaves, yet I have a hard time believing a Pacific crabapple has grown here in the middle of a dry forest. It looks so unlike the fruit-laden crabapples I found along Burley Lagoon last month. But there is no mistaking it. The understory varies. It has hidden habitats. It is often mysterious.

If the overstory is the main characters and the plot, the understory is the world through which they move, the story’s language, its culture, its objects and subtle inclinations. It is the residence of biodiversity, a synonym for possibility.

In another place, I duck off trail. Within a few strides, I am in a kingdom of moss. Distant sounds are dampened. Except above. An eagle flies over, and I hear the whooshes of its wingbeats. A buck deer has been here: the trunk of a willow is ragged on one side. A few brick-red russula mushrooms have been upended.

Why such a richly emergent understory here? Answering that question may be a whole science unto itself, but it has much to do with forestry practices — how DNR has done its logging, the number of mature trees it left behind, its control of invasive species, and perhaps most importantly the care it has taken with soil.

Mushroom season drives home the notion that a great deal of life happens underground. You’ll occasionally find circular thickets of blackberries at 360 Trails. These are former landings, where the soil was ground up by heavy machinery and log decks. Our invasive species seem to love such upended soils.

Elsewhere the soils are rich with diverse native species. Healthy soils require many ingredients. Organic matter, a topsoil-subsoil structure, aeration, water retention and drainage, shade from vegetation, natural mulch from fallen leaves, nutrient supply and cycling, animals, fungi, microbes — all contribute to the diversity of the understory. There are many ways to ruin the recipe.

The slow degradation of soil is one of the main concerns about the rotation-over-rotation impact of even sustainable forestry.

A site’s growth potential will diminish over time unless great care is taken to protect its soil. The other concern, when forests are treated as crops of trees, is a systematic loss of biodiversity.

So maybe we should judge forests as much by their understories as by their timber.

I move into a terrain of widely spaced firs. Salal is everywhere. Oceanspray and huckleberry protrude alongside young firs. A few old Scotch brooms are dying out.

And this is chickaree land. I hear their ringing calls from three directions. One yells at me from point-blank range, face down on a big fir’s trunk.

You think squirrel and you think tree but look all around it. Look at the abundance of berry bushes and mushrooms and insect habitat. Squirrels eat far more than seeds. Sure, this tree it’s on, its safe spot, is crucial for the squirrel’s survival, but it would be a poor squirrel indeed if the understory were not so lush.

And how much richer might we be, how much healthier, if we worked ourselves into a chickaree-type relationship with the understory? There is much to be gleaned, medicines for body and soul. The poet George Herbert wrote of wild herbs, “More servants wait on man / Than he’ll take notice of; in ev’ry path / He treads down that which doth befriend him.”

Even Powers could not keep the understory out of “The Overstory”: “If memories change the pathways of the brain, then the trail must still be there. It’s just a matter of waiting for the wild things to emerge out of the understory.”