It’s cold and damp this morning in West Virginia’s Kumbrabrow State Forest where Conservancy stewardship manager Mike Powell and his colleagues are prepping for a busy morning restoring red spruce seedlings. Everything looks ready when Powell suddenly pulls out a small plastic bag of grayish powder and grins, “Time to make the ‘shroom juice!’”
Wait. What is ‘shroom juice and should I be worried? Is it possible I’ve somehow stumbled across a weird foresters’ rave here on this open ridge near the oddly named Meatbox and Potatohole Trails?
Well, no, not exactly.
For one thing, it’s not that kind of ‘shroom juice; for another, it’s for the seedlings, not the people, which is good because after Powell mixes the powder with water in the bottom of a 5-gallon bucket, the dark liquid coming to viscous life — about the color and consistency of a minimally blended blackberry and kale smoothie — doesn’t look very appetizing. At least to me.
The red spruce seedlings are apparently another story.
“They love it,” says Powell. “And it loves them back. Our restoration work over the last five years has shown that red spruce seedlings dipped in ‘shroom juice – really, a mix of mycorrhizal fungi found in the soil – just before planting appear to have a much better survival rate and recover from the shock of planting much more quickly than seedlings that haven’t been dipped. It’s like an inoculation.”
So ‘shroom juice is some kind of secret restoration ingredient?
“Well,” Powell sounds thoughtful, “Yes and no. Our ‘shroom juice is actually a mixture of [six] mychorrizal fungal species normally found in the soil in this part of West Virginia. It’s not really a secret ingredient. It’s just that scientists are only recently coming to appreciate the necessary role mycorrhizal fungi play in maintaining a healthy relationship between soils and plants all over the world. And how activities like logging, agriculture and urbanization change those relationships.”
True confession: It took me 10 tries to correctly pronounce, let alone spell, “mycorrhiza” (pronounced “my-kor-rye-za.” You’re welcome). And honestly, the first time I heard it mentioned, I thought mycorrhiza was the name of some obscure, but fancy pizza topping.
Pro tip: it’s not. Mycorrhiza is a symbiotic relationship between plant roots and fungi. In my pizza-topping defense, some of these fungi do grow mushrooms. There are about 50,000 known species of mycorrhizal fungi around the world. It’s a slight imprecision, but in the interest of keeping it all straight, I think of the multiple types, with names like arbuscular, arbutoid and ericoid, under the single mycorrhiza umbrella term. Like “mushroom” covers many different species of individual mushrooms.
The important thing to know about mycorrhizal fungi is that about 90 percent of the world’s vascular plants – from trees to orchids to ferns – form these relationships and many can’t live without them. The plants are adapted to the fungi and the fungi to the plants in classic symbiotic relationships that vary widely among species.
“Mycorrhizal fungi have little underground root networks – the hyphae — and those grow around the roots of the tree,” explains Powell. “So you’re looking at an extension of the tree’s root system so that the trees can actually draw in moisture and nutrients from a longer, deeper area than what the roots themselves can do.”
And because the fungi continue to spread as they grow, they move through the soil and form a kind of network that connects even different types of plants in a forest. It’s kind of mind boggling to consider how these fungi might connect shrubs and trees together in a network that until relatively recently we didn’t even realize existed. The mycorrhizas also connect the forest and the soil to the rocks of the earth – twining into small cracks and crevices where even the smallest tree roots can’t go.
Mycorrhizal fungi are like the thinnest, finest threads of a fabric – the ones that weave it all together. And right now, people are cutting those threads without really understanding what else we might be unraveling.
All of which brings us back to those multiple types of mycorrhizal fungi, like ericoid. Scientists now know which fungal types form relationships with which specific plants. That knowledge coupled with the national vegetation mapping program, LANDFIRE, allowed TNC scientist Randy Swaty and his Northern Arizona University colleagues to produce national maps of these fungal relationships – for the first time.
“There’s much we don’t know about soil microbes,” says Swaty. “It’s like all the new studies into the human gut microbiome. The more we look the more we find. Our hope is that ecologists will look at these maps and consider variables they may not have considered before. I hope they’ll use them, and help us continue to improve them with more and more specificity.”
Mycorrhiza and Red Spruce in West Virginia
The red spruce of West Virginia, like the ones Powell and his partners in the Central Appalachian Spruce Restoration Initiative are restoring today, are Exhibit A in what happens when the mycorrhizal threads that bind a tree and its soil are severed by logging or other disruptions like fire. The trees can have a hard time coming back.
Hardwoods can regenerate from the existing root mass, but red spruce rely on the existing seed bed. If the mycorrhizal species the spruce depend on are missing or impaired, the seeds – even if they germinate – often struggle to get the nutrients they need. Which is where the ‘shroom juice comes in.
“We dip about a quarter of each red spruce seedling’s roots into the juice,” says Powell, “just before we plant them. It gives them that head start for long-term survival. You can’t restore one without the other – the trees need the mycorrhizal fungi, the mycorrhizal fungi need the trees. And as the forest and the trees grow, the mycorrhiza will spread through the soil and eventually provide the needed conditions for the spruce to grow from seed beds without needing that little help from their friends.”
Until that happy day, the ‘shroom juice will continue to flow, so to speak, in this part of the Appalachians.
Since 2009, when the Spruce Restoration Initiative began, the Conservancy and its partners have planted more than 900,000 red spruce across West Virginia.
Editor’s Note: While many home improvement and gardening centers sell soils that include mycorrhizal fungi for home use, soil ecologists and foresters advise against their use on lawns and gardens. Using off-the-shelf mixtures can introduce potentially invasive microbes to your soil. In West Virginia, Conservancy scientists use quality-controlled, highly specialized mycorrhiza mix suited for the soil conditions and needs of red spruce in local geographies. In other words, please don’t try this at home.
LANDFIRE is a shared program between the wildland fire management programs of the U.S. Department of Agriculture Forest Service, and the U.S. Department of the Interior. This multi-partner program includes The Nature Conservancy, and produces consistent, comprehensive, geospatial data and databases that describe vegetation, wildland fuel, and fire regimes across the United States and insular areas.