I found the following info at http://www.800oakwilt.com/biostimulants.htm:

"A productive, biologically active soil can contain as many as 45 quadrillion microorganisms in the rhizophere or root zone of 1,000 square feet area around a tree. This population consists primarily of bacteria, actinomycetes, fungi, and algae....
Fungi are involved in organic matter decomposition, mycorrhizal associations, and tree diseases. Mycorrhizia (root fungus) are known to improve nutrient and water uptake. In fact, mycorrhizal associations have been shown to provide inter-specific transfer of phosphorus and other nutrients. Endophytic fungi form associations with plants and discourage insect predation. Actinomycetes decompose organic matter, and are also capable of producing antibiotics that may confer disease-suppressive qualities."

My question is this: Will spreading cornmeal on the ground around trees kill these beneficial fungi residing in the soil and on the tree roots? Thanks.

I would have to say 'no' simply because if that were the case you'd see a serious hit in the tree' health afterward and so far every example of using cornmeal has shown health improvement in trees and plants.

_________________
Shepherd of the Trees
It is not our part to master all the tides of the world, but to do what is in us for the succor of those years wherein we are set, uprooting the evil in the fields we know so that those who live after may have clean earth to till.

Somebody pull up this research! I know it's hidden in an archive around here... In any case I have never seen anything but benefit to adding cornmeal as an amendment.

My understanding is that it encourages the growth of the beneficial fungus, working like many other things in the natural world that attack the detremental organisms and encourage the beneficials.

Go figure that somebody up there made things so sensible!

Kathe