I decided a while back to curtail mycorrhizal soil inoculation until seeing more definitive science about its effectiveness on mature trees. But with trees here in the southeast in serious danger of dying from drought stress, I'm considering using it in combination with large mulch bed installation in an effort to maximize absorbing root water uptake beneath the beds. Is anyone aware of any recent research, or tried this treatment for drought stress? At this point, I'm about willing to try anything that won't hurt the trees to try and pull them through an even hotter and dryer summer than the last few. Thanks for the advice and insight.

Tom

Reply to post by Tom Watson, on June 13, 2000 at 14:53:15:


Tom,

Are mycorrhizzae or mulch somehow to be substituting for water. There are few things richer in both of the "suggested drought solutions" than a forest floor and, as I remember it, forests too die from droughts.

I absolutely understand the drive to find the magic bullet, I've spent a great part of my life on those adventures, but symbiotic mycorrhizae depend on the tree and are fragile creatures indeed. Independent flora and fauna generate water as a result of their own "respiration", but their output may never be of significant use to a tree.

The mulch inhibits evaporative loss from the surface area, but it also inhibits the movement of water down into the soil through that mulch. Many rains do not effectively penetrate the mulch thicknesses seen around most these days.

That's part of why tree roots mine mulch so thoroughly well up above the level where roots are found. If the rain doesn't get down to the roots, the roots rise to meet it.

If rains don't come, conditioners or agents in the soil, do not manufacture the needed water. The tree is a gross user of water, comparatively, and some how keeping the roots more damp do not meet the macro-needs of the larger creature.

This is not to say, give up. Not at all. Being protective of the roots until the rains do come may be of greater benefit than anything we can do short of providing the actual water. My methods in Chicago were the most careful and frugal of water placement and, from my research, were needed only once in the course of a protracted drought.

It was my intention to keep trees alive--and the concepts did just that--with water and new techniques.


Bob Wulkowicz

Reply to post by Tom Watson, on June 13, 2000 at 14:53:15:

Bob, good points. With austere, aggressively-enforced water restrictions, however, watering isn't an option. I'm trying to find anything that will help trees best utilize what little water is available. I'm eager to here any suggestions for helping drought-stressed trees make it through yet another hot, dry summer. Your comment about thick mulch beds was helpful. I've spread some beds thinner and turned others that have matted on the surface. I've found that wood chips from disc chippers are a much more penetrable mulch than those from drum chippers that tend to chunk rather than shred. Beds composed of the more chunky wood chips are the ones that have form the matted surface crusts, as they tend to form aggregates.

Thanks,
Tom

Reply to post by Tom Watson, on June 13, 2000 at 14:53:15:

Tom

You could follow up Bob W's comments regarding mulch by looking up an old thread 'Compaction of Soils' on UKTC (www.oak-wood.co.uk/uktc/) of April this year.

The periodic application of a shallow (50mm or even less)woodchip mulch (preferably of the species to which it is being applied, or one of it's natural associates) should improve or maintain the absorptive properties of the A horizon soils, thus reducing surface water runoff, particularly on sloping sites. Not much help for your current predicament, but valuable in the longer-term.

A perforated, reflective polythene sheet should help reduce/stabilise temperature at the soil surface and substantially reduce evaporation, particularly of light rainfall.

Mike Ellison

Reply to post by Mike Ellison, on June 13, 2000 at 14:53:15:

Dear Sir,
Presently Iam working on role rhizosphere in I
taxus baccata. Please send the relevant information.

sincerely yours,
rajeev