In article ,
The Cook wrote:

On Tue, 13 Apr 2010 14:41:14 -0700, Billy
wrote:

In article ,
The Cook wrote:

I seem to remember that wood as it decomposes uses up the nitrogen in
the soil. Not really good for the garden. Old wives tale or true?

In terms of both its physical and chemical properties, wood is an
exceptionally difficult substrate to degrade. One of the principal
reasons is that wood contains very low levels of nitrogen, which is
needed to produce the enzymes that degrade the main structural polmers
of wood - cellulose (about 40-50% of the dry weight of wood),
hemicelluloses (25-40%) and lignin (20-35%).

The lignin component also presents a barrier to wood decay because
lignin is a complex aromatic polymer that encrusts the cell walls,
preventing access of enzymes to the more easily degradable cellulose and
hemicelluloses. In addition to these points, wood often contains
potentially fungitoxic compounds, which are deposited in the heartwood.
In broad-leaved trees the toxic compounds are usually tannins, well know
for their ability to cross-link proteins, making animal skins resistant
to decay. In contrast, conifers contain a range of phenolic compounds
such as terpenes, stilbenes, flavonoids and tropolones. The most toxic
of the tropolones are the thujaplicins which act as uncouplers of
oxidative phosphorylation; they are particularly abundant in cedarwood,
making this a naturally decay-resistant wood for high-quality garden
furnishings, etc.


http://www.biology.ed.ac.uk/research...iology/woodrot
s.htm

When the nitrogen is no longer needed for enzymes or fungal growth, it
is released back into the soil environment for use by other microbes,
and plants.


Actually my husband and I were discussing the cedar chips versus grass
clippings as mulch for the rhubarb. He is thinking that the cedar
would be there for a long time. I am thinking that the chips cost
money and would get moved into the other parts of the garden. Grass
clippings a free and do provide some nutrients for the plants as well
as helping to keep the weeds down. We do have about an acre of grass
that needs to be mowed regularly.

Cedar chips would be the opposite of grass clippings as a mulch. Are we
talking mulch as a ground cover, or mulch as a nutrient? Cedar chips
breakdown slowly, making them a good ground cover, but a poor nutrient.
Grass clipping break down quickly, making them a quick nutrient source
for soil microbes.
----
"wood often contains potentially fungitoxic compounds, which are
deposited in the heartwood. In broad-leaved trees the toxic compounds
are usually tannins, well know for their ability to cross-link proteins,
making animal skins resistant to decay. In contrast, conifers contain a
range of phenolic compounds such as terpenes, stilbenes, flavonoids and
tropolones. The most toxic of the tropolones are the thujaplicins which
act as uncouplers of oxidative phosphorylation; they are particularly
abundant in cedarwood, making this a naturally decay-resistant wood for
high-quality garden furnishings, etc."
http://www.biology.ed.ac.uk/research...Biology/woodro
ts.htm
----
Am I missing a piece of the puzzle?
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.youtube.com/watch?v=Arn3lF5XSUg
http://www.thirdworldtraveler.com/Zinn/HZinn_page.html