Re: MGS/ Ran Pauker lecture in Berkeley

--- K1MIZE@aol.com wrote:

> I've also noticed that many native oaks, in
> particular the more-or-less 
> deciduous Valley Oak (Quercus lobata) and Blue Oak
> (Q. Douglasii), in 
> oak-savannah habitat, often have a patch of green
> underfoot that mirrors the 
> drip-line, when all the grasses and forbs for miles
> around have assumed the 
> gold of summer or gray of autumn.  Whether this is
> an effect of catching and 
> increasing precipitation, or (as I suspect) a result
> of protection from the 
> effects of the scorching sun, remains to be seen. 
> Providing some shade, 
> particularly during the hottest months, can really
> make the difference for a 
> lot of plants in our climate.  I've even noticed
> this "shade effect" on my 
> own lawn.

Kurt, I think the shade is the bigger factor in
keeping things green longer into the dry season.

> <<It was amazing to me to hear that turf grasses
> could
> be maintained in 40C temps in summer with only
> monthly
> irrigation.>>
> 
> Amazing to me, too.  Here in the Central Valley of
> California, I would be 
> willing to bet that there is virtually NO lawn,
> including one of Bermuda or 
> St. Augustine grass, that could be maintained with
> only monthly irrigation.  
> Kept alive, perhaps, but not attractive.  Lawns here
> are generally maintained 
> in summer with a ONCE OR EVEN TWICE DAILY irrigation
> regime.  You can get by 
> with every other day, or even skip two days every
> once in a while, but the 
> appearance of your lawn will suffer as a result.  

Kurt, what type of lawns are these?  I would think
that you could stretch out lawn irrigation to at least
every 3/4 days in your area with the more drought
tolerant grasses and deep watering to penetrate to 18
inch depth.  Having to water every day would seem to
indicate too shallow watering for your climate, as
even in Riyadh, Saudi Arabia, hybrid Bermuda grass
could go 2 to 3 days between irrigation without
looking too stressed, and we are talking 120F/50C at
height of summer.  If you are only watering for 5 to
10 minutes at a time and have loamy clay to clay
soils, I could see the necessity for daily watering.

> Many California natives, particularly those in the
> Central Valley, although 
> they apparently survive on rainfall alone, are
> actually very dependent upon 
> the snowmelt runoff from the Sierra Nevada, which
> once provided a sort of 
> natural irrigation during the dry months of the year
> in the form of a high 
> water table and seasonal flooding.  Now that most of
> this water is being 
> siphoned off for human use, many once-widespread
> habitats and the plants they 
> supported are in danger of extinction.  Valley Oak
> riparian forest, in 
> particular, is down to about 1% of its former range.
> 
The loss of ground water has not been as great a
hazard for Valley Oaks, as habitat loss due to
development has probably been.  Rodent depredation and
 cattle grazing in fields with remnant populations has
also greatly reduced the growth of seedlings, so that
the populations tend to be all of one age, with now
young replacement trees coming along.
> 
> I think that's pretty close to San Diego, which gets
> around 11 inches per 
> year.

I didn't make the comparison with San Diego as the
temperatures are more desert like for the Kibbutz,
which although only 12 kilometers or so from the
Mediterannean Sea, is considerably hotter than coastal
San Diego, and much more sparse for native vegetaion.
> 
> Sorry I missed the lecture and meeting.  Sounds like
> it was interesting and 
> informative.  As I get older, I find myself less and
> less inclined to spend 
> my few remaining hours watering the garden...
> 
> Kurt Mize
> Stockton, California
> USDA Zone 9

I know what you mean about watering, it does get old
after awhile, and I am thankful that most of my garden
has automatic drip irrigation now, so that I don't
have to manually water everything.  Many of the most
intensive gardeners here in the Bay Area swear by
manual irrigation, as being the best way to really see
all of the garden and keep tabs on things, but it does
take time.
> 


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