Very interesting article. There is still very much to learn about mycorrhizal fungi, I believe scientists have only started to understand how it works.

I read somewhere else that mature spruces can send nutrients to seedling spruces via mycorrhizae to give them a good start. That's just another aspect of the wonders of mycorrhizal fungi.

So, if I understand correctly, this Canadian native pine grows much better in Sweden for reasons pertaining to the micro-organisms in the Swedish vs. Canadian soil. Leaving the question of how much of that is the absence of harmful vs. the presence of beneficial organisms.

A somewhat related topic came up in another thread about the desirability of exotic trees which are relatively pest-free, although I think the focus there was on native trees offering food for native creatures (some a.k.a. 'pests'), vs. some exotics being like a 'plastic tree' - a structure but not a food source. Of course, such a tree would be less likely to trigger insecticide use such as imidacloprid-based products that could harm bees.

I bring that up because a tree free of 'pests' could reasonably be able to channel more resources into vigor/growth. Most soil microbes don't grow into pretty butterflies & such, so they don't get as much love, but I wonder what large-scale alteration of soil micro culture will mean for the environment?

Richard.

My theory is invasives grow better because local pests are not as in tune to destroying them.

In this particular case it seems to depend on good mycorrhizae. This fungus is helping the trees to gather nutrients, minerals or something like that.

Right.....and the other aspect-that of possible freedom (in the Swedish example) from certain soil pathogens that may have built up over time in the BC example may have bearing on this as well. Not entirely known at this point.

I offer it only as a rhetorical thing-to dispel some of the simple-mindedness of the natives-only camp while also offering a glimpse into the extreme complexity of soil interactions, about which, as someone said above, we are just beginning to learn.

And yes, it has been proven that through the mycorrhizal network, big momma fir tree can send photosynthates (carbohydrates) to a little, suppressed individual some distance away! This was very easily shown in research using radioactive tracers. And it is almost immediate. The researches added in the iodine or whatever they used, and within seconds, could follow it using a Geiger counter...moving towards the little guy. We know almost nothing.

Oaks develop a mycorrhizal "network" where the roots connect (indirectly via the fungi) between individual trees and they support each other to the disadvantage of other trees. In the oak forest if you carefully remove the leaf-litter into the blackish humus you can see the white fibers of the mycorrhiza.

All species, not just oaks, do this. Further, it is beginning to look as though this sharing of nutrients and other processes is NOT restricted to within a given species. That is, it now appears that a tree of one species may be able to "communicate" with one of another species via this network.

There's way more to it. It also appears that certain soil bacteria can "prime" the area around a tree's roots for mycorrhizal development, so certain bacteria are involved as well. This is about as far from "how much fertilizer should I dump around that tree" as it could get. Indeed, in cases where lots of major nutrients are present in the soil, these soil microbes are inhibited. That is, the whole shebang works better when nutrients haven't been artificially increased.

The rhizosphere-that miniscule region around plant roots, is an area of extreme complexity. The plants exude substances into the soil, the bacteria and fungi can use these exudates for their own purposes, and in turn, can sequester nutrients for the tree that would otherwise be unavailable. For example, mycorrhizal fungal species have the ability to extract both phosphates and evidently nitrogenous compounds as well from sheer rock.

Finally, we hear a lot these days about carbon storage in natural systems. Well, it turns out that in the forest system, more carbon is stored below ground-in these fungal networks-than in all of the trunks, branches and foliage of all the trees within that stand. Pretty heady stuff, and it sure goes to show how amazingly ignorant we are.

edited to add: I somewhat misspoke up there-it is the total below-ground carbon that exceeds the above-ground, not just that from these hyphal structures of the mycorrhizal fungi. Still crazy to ponder upon.

Tom, thanks. Read somewhere that the North American forests did not effectively colonize northward after the glaciers receded until the mycorrhizal network re-developed.

That makes perfect sense, once one realizes how vital these associations are. In fact-and somebody correct me if this is in error-but I believe that it is not even yet known which came first, functional root systems on trees or these microbial helpers. Mostly it seems that otherwise saprotrophic fungi somehow "learned" to quit decaying wood and obtaining their carbohydrates from higher plants instead.......and that likewise, trees somehow "learned" that it made more sense to do this trade-off with the fungal partners than to expend the energy to create the type of root system that it would take to obtain all the nutrients required. Crazy stuff....but that's the world for you.

Also read that trees "signal" certain fungal species to come work with their root systems by exuding certain chemicals into the soil to attract them. There's an awful lot of communication going on in the dirt!

My first thought when I saw the thread title was, "Of course. All those invasive species. Russian olive in southern alberta. Norway maple almost everywhere. Sea buckthorn. Caragana. Manitoba maple.

"We know almost nothing." Now that is a statement I can agree with! Biological systems are, as some scientists are fully aware, irreducibly complex. We haven't begun to comprehend everything that goes on in nature, let alone our own brains.

Now Tom, just what are you suggesting by saying a plant or other organism "learns"? I can see how there were opportunistic situations that resulted in a change in the way a tree or fungus operates, but "learning" seems a bit of a stretch to me. Guess it depends on how you're defining "learned".

Yeah I put it up in those italics because I mean it (learn) only in the most general, non-specific way possible. I would expect it was the normal range of genetic mutations and genetic feedback loops as for any other adaptation.

Sherwood, indeed. Just watched bit of video of our local Wild Ones chapter president giving a talk to some group, and when the line got trotted out about how native plants adapt more readily, etc....the usual plank...that's the first thing I thought of too, and no doubt the fact I get involved in control of invasive plant species lets such matters rest close to mind for me.

maybe the reason why dawn redwood grow largest in new jersey

In passing: "Invasive" is often way over simplified. Common Tansy and and Orange Hawkweed are nominally invasive for my part of Alberta. However my open land isn't grazed right now (except for hoof rates --err-- deer) With long grass my 3 tansies just sit there. The only place I've found hawkweed is where I mow. So perhaps invasive needs to be qualified with conditions.

Ecology is just barely a science. What we need is a field of ecological engineering.

I'm not sure that it's 'irreduciably comples' I think it's just very very messy.

The engineering will happen when we can figure out what bits we can ignore. We have a start on that with 'indicator species' where the presence or absence of a particular speices tells us gobs about what else we will find there. This may mean that by monitoring for a small number we can figure out to +- 25% the numbers of 90% of the rest of the biomass.

Hey, it gives me an excuse to wander in my collection of forests.

(My collection: http://sherwoods-forests.com/Our_Forests/Our_Forests.html)

Guy out of Salt Lake City did his dissertation on disturbed urban soil and found that it takes anywhere from 30-50 years for soils to "return" to pre-disturbance levels of critters in soils.

Many folks in restoration already know heavily disturbed soils don't support natives well at all.

Okay, while the forum conventional wisdom tends to be 'don't amend the soil' when planting, riddle me this...if someone is planting a tree in his yard (native species if it matters, but I suppose any zone appropriate tree), let's say he goes out to a forest area with a shovel & bucket, grabs a couple of shovels of soil from the forest floor, and when he plants his new tree (from a vendor) in the yard, he puts that forest dirt in the hole around the roots. Not the entire backfill; just a shovel full or two to 'seed' it with beneficial microorganisms.

Any idea whether that's apt to make a meaningful difference in how the tree does? Odds of survival, time to acclimation, growth rate, etc...

Granted, a lot of the microbes will due to environmental changes related to the move, new conditions, etc...but not all of them.

Richard.

let's say he goes out to a forest area with a shovel & bucket, grabs a couple of shovels of soil from the forest floor, and when he plants his new tree (from a vendor) in the yard, he puts that forest dirt in the hole around the roots.

Much preferred to consuming products at the bigbox. People have been doing what you describe for a long time.

As a teenager, I went out to the woods and dug up a fern for a shady corner garden by our house. Scored major points with my mom. A few years later we had a lady slipper orchid in the bed too. Had to do some swift explaining to our sierra club neighbors that we weren't orchid nappers. (It's protected where I grew up.)

In my tree farm operation I use about 1/3 field soil just so that the mix isn't totally sterile.

I seen a documentary where a parent tree was giving nutrients to its offspring through mycorrhizal connections

Yes Viper-probably what I saw too. Radioactive iodine tracers in photosynthate (sap) read via Geiger counter? That's the one I saw. And it took only minutes if I recall correctly! We always hear about the competition between plants in a stand. But it is starting to look as though the mutualistic stuff outweighs this competitive thing in many important ways.

yeah it was called What Plants Talk About.....starts @ 41 min