I learned this "secret" from an extension agent who had an existing
agreement with the electric company to take their wood chips, and his
extensive garden now has 12" or more of mulch throughout, including around
his citrus. It's a win-win situation -- they don't have to pay the county
to dispose of their chips, and the user gets an endless supply of free
mulch.

Regards --



Dear Regards

As for trees as mostly for woody plants which maintain a symplast.

With respect. When mulch is more than 3-4" thick, the non woody roots tend
to grow into the mulch. With the finer gradation of mulch, it dries out
first. When a leaf is shed, first the leaf dies and then a abscission zone
if formed and the leaf is shed. The abscission zone made up mostly of
suberin. On trees like pin oaks and young beech, the abscission zone do not
form for some reason. They hold on to their leaves over winter often. If
you take and break off a leaf at the stem you will see that there is green
tissue. Chlorophyll has to be constantly manufactured. Now with
mycorrhizae and none woody roots the opposite happen. First the abscission
zone is formed and then the mycorrhizae and non-woody roots die and are
digested by microorganisms. Now, when the mulch has non-woody roots growing
in it and the mulch dries out and the roots or mycorrhizae die, the
abscission zone doe not form. This leaves an opening not sealed. Small to
us but huge to micros that can incite disease.

Nurse logs hold water for dry times. A log that is 1 1/2 feet in diameter
of larger and at least four foot long can hold water as a reservoir when it
reaches that ecological stage. That is very important in forest health -
downed wood with soil contact will become a water reservoir for trees during
dry times. Mulch comes in different gradations. Nurse logs will have
non-woody roots and mycorrhizae growing in them and this is a good thing.
If you are using common mulch when roots grow into mulch you have too much
mulch.

Here are some articles on the topic:
http://www.treedictionary.com/DICT2003/shigo/CHEM.html

http://www.treedictionary.com/DICT2003/shigo/RHIZO.html

http://www.treedictionary.com/DICT2003/shigo/WATER.html

http://www.treedictionary.com/DICT2003/shigo/index.html

FRESH CHIPS!



First allow me to define some terms. The "symplast" is a webwork of living
cells (parenchyma) in branches, trunks and roots of trees that still produce
leaves or needles. "Mulch" is anything that will benefit the microorganisms
of the soil. You do not have to agree yet you will know what I mean.

Proper mulching can be very beneficial for the soil as well as your trees.
I. e., if the correct material is applied in the correct way. First, do
not use fresh chips. The parenchyma cells of the symplast contain
protoplasm. When we chip a branch with symplast the protoplasm gets smeared
all over the place. This can attract undesirables that can do and do do
nasty things to trees above as well as below ground. Of course if the
branch chipped is symplastless the chips can be used immediately.
Composting fresh chips in a pile for one year should be enough to safely
apply them as mulch. Composted wood chips make great mulch for trees and
their associates with many benefits.

Now here is where many people make the big mistake -
application. Keep the mulch back from the trunk flair at the base, at least
6 inches. Mulch should not touch the trunk! The mulch should be 3 - 4
inches thick and flat. Due to the fact, that turf roots grow deeper than
the non-woody absorbing roots of the tree, we suggest not to dig out the
turf. The turf could be cut low and then the mulch placed on top. DO NOT
INJURE THE TREE WITH A STRING TRIMMER!

The outer bark of trees is primarily made up of suberin. Which
is long chains of fatty acids. There is carbon but the chains of carbon and
hydrogen in suberin are so varied that few enzymes from microorganisms are
able to cleave it for an energy source. For this reason we suggest not
using all bark for mulch. Composted wood and leaves has the carbon required
by beneficial microorganisms.

Also, the more composted the wood chips, the more you reduce
your chances of artillery fungus on your house.

Mulch applications should be maintained on a yearly basis. For more on info
look up "Mulch" or "Symplast" at www.treedictionary.com.



I hope this helps the trees. I hope you get help from this Regards.




--
Sincerely,
John A. Keslick, Jr.
Consulting Forester & Tree Expert
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.