"Roy A. Fletcher" wrote in message
...
I'm trying to locate a site that discussed the detrimental
effects of heavy watering of tree trunks in irrigated areas.
In a public park in my town, we have had 22 Lawson cypress
and 12 Douglas firs die due to root rot (Phytophthora and
Phellinus weirrii are the identified pathogens). All of
these trees have had their trunks at ground level thoroughly
soaked because they sit in the middle of irrigated ornamental
planting areas or lawns. Their roots are also thoroughly soaked
as often as once a week.
Any help on locating the lost site would be much appreciated.

Regards. RAF

Not sure what site in specific you are referring to, but there are many that
discuss root rots occurring as the result of over-irrigating - this is
probably the number one cause of fatalities in mature trees, not, as many
folks think, drought. Established conifers, specially those which are
summer drought tolerant natives of the west coast such as Doug fir and
Lawson cypress, need NO supplemental irrigation and automatic sprinkler
systems, like those in public parks, need to be zoned very carefully so as
not to overwater. And I'm sure you can encounter equally as many sites that
will address crown root rots from either excessive mulching around trunks or
the situation you describe.

Both of these are pretty commonly known situations by anyone with a
horticultural background, certainly at least someone in your parks
department - were you looking for the site for documentation of the problem
or just curiosity?

pam - gardengal