U of A expert contests popular claims about a "wood-wide web":
The idea that forest trees can "talk" to each other through a connective underground web of delicate fungal filaments tickles the imagination.
In fact, the concept is so intriguing, it's taken root in popular media, from a popular book to podcasts, TV and radio shows.
Dubbed the "wood-wide web," the idea that underground fungi allow trees to share resources with their seedlings — and even protect them — definitely puts the "fun" in fungus.
But the science behind those ideas is unproven, cautions University of Alberta expert Justine Karst.
In a perspective published in Nature Ecology & Evolution, Karst and two colleagues contest three popular claims about the capabilities of underground fungi known as common mycorrhizal networks, or CMNs, that connect roots of multiple plants underground. Fungi are living organisms such as moulds, yeast and mushrooms.
"It's great that CMN research has sparked interest in forest fungi, but it's important for the public to understand that many popular ideas are ahead of the science," says Karst, associate professor in the U of A's Faculty of Agricultural, Life & Environmental Sciences.
While CMNs have been scientifically proven to exist, there is no strong evidence that they offer benefits to trees and their seedlings, the researchers suggest.
[...] "Distorting science on CMNs in forests is a problem because sound science is critical for making decisions on how forests are managed. It's premature to base forest practices and policies on CMNs per se, without further evidence. And failing to identify misinformation can erode public trust in science."
[...] There is a great deal scientists do actually know about the value of mycorrhizal fungi in forests, Karst adds.
The fungi draw nutrients and water from the soil and pass those to the trees, and also protect the roots from pathogens. And by using and storing carbon from the trees, the fungi also benefit the forest.
"Mycorrhizal fungi are essential for the growth and survival of trees, and have an important role in forest management and conservation practices," says Karst, "even if trees are not talking to each other through CMNs."
Journal Reference:
Karst, J., Jones, M.D. & Hoeksema, J.D. Positive citation bias and overinterpreted results lead to misinformation on common mycorrhizal networks in forests. Nat Ecol Evol (2023). https://doi.org/10.1038/s41559-023-01986-1
(Score: 2) by ElizabethGreene on Monday April 03, @03:36PM (4 children)
My recollection is the experiment claiming fungi webs between trees was based on "feeding" isotope tagged something something to one plant, finding that transported to another distant plant, and finding concentrations in the mycelium sufficient to explain the underlying transport. The source for this was probably one of Paul Stamets books, possibly Mycelium running.
(Score: 2) by Reziac on Tuesday April 04, @02:09AM (2 children)
Maybe the fungi use the trees, not the other way around...
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by ElizabethGreene on Tuesday April 04, @01:52PM (1 child)
IIRC, the interconnections vary by each species, geography, soil composition, and in many cases are not well understood. I.e. In one set of circumstances the fungi are parasitic, but the same species in a different circumstance are symbiotic where both benefit.
(Score: 2) by Reziac on Tuesday April 04, @02:03PM
Woodlands being so highly variable, and nature being so opportunistic, I'm sure there's every possible sort of relationship.
But it's amusing to consider that this particular research may have it backwards.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 3, Informative) by dw861 on Tuesday April 04, @03:50AM
Simard, S., Perry, D., Jones, M. et al. Net transfer of carbon between ectomycorrhizal tree species in the field. Nature 388, 579–582 (1997). https://doi.org/10.1038/41557 [doi.org]
(Score: 2) by DannyB on Monday April 03, @05:05PM (1 child)
Have the trees evolved a protocol which is routable?
How often should I have my memory checked? I used to know but...
(Score: 3, Funny) by ElizabethGreene on Tuesday April 04, @02:01PM
I assume they use spanning tree.
(Score: 4, Interesting) by Runaway1956 on Monday April 03, @05:08PM (8 children)
Some of the claims for fungi seem overblown and overhyped. But, there is little doubt that encouraging fungi in the soil makes the soil healthier. I'm seeing it right here, on my little garden spot. The more mulch I put on the ground, the "loamier" the soil gets. I'm getting my mulch from the pine woods, from the oak woods, and anyplace else I can find it. I don't just scoop up the pine straw and the dead leaves, I get a little of the soil beneath that "forest litter". I've only been at it for a year or so now, but my soil does have fungi growing in it, the soil is lighter and easier to work, and it just looks, feels, and smells more like soil.
Further, "no till" practices are looking good. I planted a corn patch last week, without tilling at all. I walked down the rows, poking my jab planter into the ground, and releasing a corn seed. The planter pokes down through the leaf mulch, goes a full 2 inches into the ground most of the time. Here and there I hit a hard spot, either a rock, or a root, or maybe the soil is still that compacted. But, the soil is coming alive.
Typically, gardeners "hill" their corn, in an attempt to cover those stabilizing "roots" that always show above the ground. This year, I intend to cover all of that with pine straw, instead of disturbing the ground. If I don't run a tiller down those rows, mulching instead, the soil will stay moist, or even wet, instead of drying out.
No, I don't believe everything I read about those mycorrhizal fungi, but I'm happily encouraging them to grow in my soil!!
Nitrogen is low throughout my garden, because of all the brown mulch material I've put on the garden. But, I can fix that with some chicken litter!
Abortion is the number one killed of children in the United States.
(Score: 3, Interesting) by Reziac on Tuesday April 04, @02:13AM
So long as you don't wind up with a different sort of fungi, such as corn smut...
Hilling isn't to cover the side roots (which don't need covering). It's so you can flood irrigate between the rows without drowning the corn, and the water soaks in below the plant so encourages deep roots.
I flood irrigate, so my entire garden is in raised rows.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by quietus on Tuesday April 04, @12:10PM (6 children)
What do you refer to with pine straw? If you're referring to something with pine needles in it, be warned: you'll be acidifying your soil, which isn't particularly beneficial for corn (or any other common crop).
(Score: 2) by Reziac on Tuesday April 04, @02:21PM (2 children)
Actually, acidifying garden soil a bit is useful -- it helps prevent potato scab, and in my observation also helps prevent deformed tubers.
https://www.gardeningknowhow.com/edible/vegetables/potato/treating-scab-in-potatoes.htm [gardeningknowhow.com]
[And alkali soil is much worse; almost nothing useful grows in it. Most gardens err on the side of too alkali.]
Normally we use sulfur to acidify the soil, but then you get strong onions. If you want to grow sweet onions, and are lucky enough to already have the necessary low-sulfur soil, you have to use an acidifier like peat moss or pine straw.
This also causes insane levels of tomato production. (I get a five gallon bucket worth off each plant. Would you like some tomatoes? How about some more?? Wait! Come back!!)
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by quietus on Tuesday April 04, @05:49PM (1 child)
That is true -- depending on your soil type (talking about a temperate climate here), the optimal pH (soil acidity) here varies between 5.2 (sandy soils) and 7.7 (clay soils).
Interesting remark about potato scab. I've once had a crop that severely suffered from it, but that was probably due to the manure put into the soil being too young; maybe 10% of my harvest gets it, normally -- I've always associated it with locally drier ground, but as you indicate, it may be that the soil is locally too alkalic.
Do you grow your tomatoes in a greenhouse, or in the open field? Manure, fertiliser, mulch, further treatment?
(Score: 2) by Reziac on Tuesday April 04, @07:31PM
Southeastern Montana... my soil is sandy loam (not enough clay component to notice), but the area trends alkali. River water (whence comes the irrigation ditch) isn't bad but our shallow ground water (20 feet) is so hard it's off the scale.
No greenhouse. The spot I use for a garden was once upon a time a corral, but last so used at least 25 years ago and has long since weathered down to dirt. When I feel ambitious I scoop it some of the ancient dried manure out of the shed, but I don't always bother. If I have used straw or lawn thatch or old leaves, I use that as covering til stuff gets established, mostly because otherwise it dries out so fast. Started adding a couple bales of peat in the spring because of potato scab. I do dig the whole thing in the spring, because otherwise I'd be mostly growing bindweed and thistles and mallow, and if you don't loosen up the soil, root crops suffer.
Anyway, all I do with tomatoes is plant each a shallow pit to hold water, and fill that up a couple times a week; they get no special care at all, other than being surrounded with half a milk jug to discourage cutworms. They get full sun and it does get fairly hot here, which they like. It does help to plant them deep, with around half the stem covered. I've experimented with a lot of varieties but nowadays I only plant Early Girl for general use, and VT100 as a cherry type. (Bonnie's if I can get them, they use deeper pots and therefore have better roots.) Grasshoppers and other pests generally leave these alone. They all get 6 feet tall and eat passing children. :)
And we should probably not discuss the one time I planted spaghetti squash... four plants were supposed to produce around 15 fruits. I gave away over 160 (some the size of small watermelons, the biggest was 8 pounds) and still had more than I could use.
I do get a lot of volunteers -- VT100 self-seed like weeds and come up everywhere, and the ferals catch up with the store-bought plants by the end of June, whether I water them or not, even tho feral tomatoes never come up til after the last hard frost. Also get a lot of volunteer peas, and have found those fall-planted peas are more heat tolerant (they come up as soon as the ground starts to thaw, so probably get better roots). I've accidentally developed a line that is a hybrid of some commercial heat-tolerant pea, and a snap type, and they will sometimes produce into August. I plant them with the corn and let them climb it.
Have also tried lots of different corn, but was only really happy with one, and now plant only my descendants of "Burpee's Triple Crown Yellow Hybrid" which nonetheless breeds true, and reliably produces in as little as 60 days.
Had some potatoes come up from true seed and found myself with a new variety (purple skin, white flesh; parents probably were Yukon Gold and a random grocery red) that tastes better and keeps fantastically well, and so far hasn't contracted scab, but only have a few to plant, hopefully will be able to keep them going.
Still working on finding an onion that does well and that I like. "Sunions" kind of ruined me. I had seed saved from grown-out centers (it doesn't have male sterility as do some varieties), but it suffered a tragic accident so I'll have to start over.
And there is no Alkibiades to come back and save us from ourselves.
(Score: 1) by Runaway1956 on Tuesday April 04, @03:57PM (2 children)
If you check the fresh, still green pine straw needles lying on the forest floor, yes, they are acid. And, pulling a handful of needles straight off the tree will be even more acid. If you get some dried out needles and check them for acidity, you'll be surprised that they aren't acid. When I walk under a pine tree and start scooping needles up with a fork, I'm getting thousands of dried out needles for mere dozens of green needles. I think the ratio varies somewhat throughout the year, perhaps there are times when I would be bringing home a really acidic batch of pine straw. Right now through late summer, it's all pretty dry.
Abortion is the number one killed of children in the United States.
(Score: 2) by quietus on Tuesday April 04, @05:17PM (1 child)
That's interesting. It is the wax (cutin) of the needles that's the starter for the acidification process. I hadn't thought about it before, but what you say makes sense: dried out needles are thinner than fresh ones, while the cuticle should prevent desiccation -- it is only logical that to get to the dried out stage, the cuticle needs to have been broken down first.
Might I ask: have these needles disappeared (been integrated into the soil) by the end of the season? And is there another reason, rather than mere availability, why you use this pine straw rather than dried leaves of deciduous trees, or mown grass? (One thing I can think about is that a layer of packed needles likely holds more air, and hence is a better temperature and water buffer.)
(Score: 1) by Runaway1956 on Tuesday April 04, @11:44PM
The pine straw disappears pretty quickly, if it is covered in dirt. "Quickly" as in 3, 4, maybe 5 months. Used as mulch, it slowly disappears into the dirt. I put ~4 inches of mulch in an area last summer, and a few weeks ago, I added another inch or two. The pine straw was either decaying, or weeds had found paths to sunlight, one or the other. Of course, I have few spots that are just one kind of mulch, or another. I might put some pine sawdust somewhere, then a bit of hardwood sawdust, then some pine straw, and I might have a layer of autumn leaves anywhere in the mix. It's all haphazard, catch-as-catch-can. It all depends on what's available when I decide to get a load of mulch.
Remember though: Any brown mulch material that you till into the soil is going to temporarily rob you of nitrogen. You'll get it all back, in a year or two or maybe more, but you'll have a nitrogen deficit until the browns finish decaying.
Abortion is the number one killed of children in the United States.
(Score: 1, Funny) by Anonymous Coward on Monday April 03, @10:54PM
If you want to know the real dirt, you've got to hear it through the grapevine.
(Score: 4, Interesting) by ChrisMaple on Tuesday April 04, @04:46AM
The only thing new here is the fungi. Continent-wide or planet-wide plant communication is a science-fiction theme over a half-century old.