On Wednesday, February 21, 2024 at 4:18:03 AM UTC+11, Fred Bloggs wrote:
> On Tuesday, February 20, 2024 at 11:00:05 AM UTC-5, Anthony William Sloman wrote:
> > On Wednesday, February 21, 2024 at 2:17:20 AM UTC+11, Fred Bloggs wrote:
> > > On Monday, February 19, 2024 at 7:05:54 PM UTC-5, John Larkin wrote:
> > > > On Mon, 19 Feb 2024 14:38:50 -0800 (PST), Dean
> > > > <
hoffma...@gmail.com> wrote:
> > > > >On Monday, February 19, 2024 at 3:19:28?PM UTC-6, John Larkin wrote:
> > > > >> It's raining and blowing. The house is shaking and trees are falling
> > > > >> here and there. There are signs on US101 that say DON'T DRIVE. GO
> > > > >> HOME. I stepped out onto the deck and liked to get blown off.
> > > > >>
> > > > >> And the sun is shining.
> > > > >>
> > > > >>
https://www.ventusky.com/san-francisco
> > > > >
> > > > > Did you have a reasonable warning time?
> > > > The weather on the west coast is chaotic, with the atmospheric rivers
> > > > wrything like snakes. The forecasts change hourly and are still
> > > > usually wrong. But there have been predictions of violent weather for
> > > > a couple of days.
> > > >
> > > > The land is fragile here, seismically young, with a thin layer of soil
> > > > over rock, and shallow-rooted non-native trees ready to topple over
> > > > with a bit of rain and wind. The eucalyptus are killers.
> > >
> > > Can't help but laugh when people think trees and shrubs will prevent landslides. They help with surface erosion but do nothing to anchor 30 ft deep soil saturated with enough moisture to reduce internal shear friction to the point of being well in excess of a stable angle of repose, the kind of failure responsible for 'slides.'
> >
> > Thirty feet of soil is not a thin layer. You've got to have plants there for very long time to build up that much soil.
>
> You don't know anything about it, fool. The soil originates from erosion of rock, not plants.
The ignorance is all yours. What you get from eroding rocks is dust, not soil. The organic content in soil comes from plants and fungi.
> > > Big trees are held steady against strong winds by an extensive system of surface feeder roots, which can greatly exceed the span of the dripline by a factor of 10x. Deep roots going down vertically do nothing to stabilize the tree, they're ground water taps.
> >
> > The fact that they are ground water taps doesn't stop them from providing additional mechanical stability.
>
> It's negligible compared to the laterals. I guess you're too dumb to observe plenty of large trees blown over, and these trees have no impediment to deep taproot / heart root development, but they do have impediment to lateral root development.
You do neglect lots of stuff that you can't be bothered to understand. I haven't observed any large trees blown over in my immediate locality but the TV news was recently full of images of large tree that had fallen in the outer suburbs. About twenty years ago our house in Nijmegen lost two old and quite tall poplars to some unusually powerful winds. We got lucky with the wind direction - one of them ended up lying just behind the house next door rather than flattening their bedroom. Poplars are always a menace. My parents house in northwest Tasmania had two at the front, and both blew over on the same - very windy - day.
> > > Problem is the urban environment doesn't allow that kind of shallow lateral development as roots are blocked from expanding by houses, sidewalk, roads, and what have you, so big trees blow over, fall on houses, parked cars, and power lines. With few exceptions, most flora is comparatively shallow rooted.
There wasn't much to inhibit the lateral development of the roots systems of any of the four poplars involved. These were big - four bedroomed - houses on even bigger blocks.
> > > The eucalyptus trees introduced by wannabe horticulturalists from Australia, who didn't know what they were doing, are the worst threat. In their native land, they grow on rocky steeply sloped terrain in soil that's nutrient depleted, meaning they stay small to mid-sized. But in the nutrient rich California soil they grow to enormous size and are extremely heavy.
>
> > They can get pretty big in Australia, which is a continent and offers a lot of different environments.
> >
> >
https://www.abc.net.au/news/2017-08-05/search-for-australias-giants-where-is-our-biggest-tree/8766292
> >
> > "In 2005 the world's tallest measured living tree was a 112.7-metre-high coast redwood growing in Humboldt Redwoods National Park, California." but
> > "Although there are claims of mountain ash (Eucalyptus regnans) in southern Australia growing to over 120 metres, the tallest ever officially measured was 107 metres. "
> > "Today the tallest living known specimen is a 99.8-metre tree called Centurion in the Arve Valley, Tasmania. It was found and measured in 2008, replacing the previous record holder, the 97-metre-high Icarus Dream in the Styx Valley."
>
> Those specimens are freak volunteers grown from vulture poop, and not the rule.
They are unusually tall - otherwise nobody would have bothered to measure them - but they occur in natural forests. Australia doesn't have any vultures now, and doesn't seem to have had any for some 50.000 years.
https://www.cnet.com/science/biology/not-an-eagle-misidentified-bird-is-australias-first-fossil-vulture/
It's a fairly old tree - if still growing. Gums of that size tend to be few hundred years old. The pulp and paper mill in Burnie, Tasmania, more or less banned eucalyptus wood more than forty years old - 1.3 metres trunk diameter - because the chemistry of their lignin content messed up the soda-recovery cycle in the pulp mill. There are a couple of similarly tall (if marginally shorter) trees nearby.
https://en.wikipedia.org/wiki/Centurion_(tree)
--
Bill Sloman, Sydney