[Arid_gardener] Question from Home-Hort WWW page

[Mark Di Lucido]

Bob

Many times blowdown is related to improper irrigation. 
1) As you stated, your tree's roots stay near the surface to take advantage
of your drip system.  If you water much deeper but less frequently, you
encourage roots to go deeper and thus have better anchorage.  Watering this
way also leaches salts below the root zone.  
2) Most mesquites, especially non-natives, form large canopies quickly.  If
the root system doesn't go deep and spread (anchor) far enough to keep pace
with this growth, over she goes.  What makes this happen often, especially
in irrigated locations, is the roots stay near the water source.  When the
tree is installed the emitters or bubblers should be located near the trunk
as the root zone is still small.  Over several years the canopy gets big but
the root zone stays small if the emitters or bubblers are not gradually
moved away from the trunk (the roots have little incentive to spread out or
go deep if they have a ready supply of water nearby.  The best analogy I
think of is a patio umbrella planted shallow.  Large wind load plus small
anchorage equals horizontal tree.
3) Pruning also can play a part.  Canopies that are too dense and not
thinned occasionally, or pruning too many lower branches to encourage faster
top growth may exacerbate this.
4) Consider a native mesquite as they don't grow as fast as the exotics and
seem to be less prone to blowing over.

Good luck

Mark D
(not a master gardener)

-----Original Message-----
From: arid_gardener-bounces at CALS.arizona.edu
[mailto:arid_gardener-bounces at CALS.arizona.edu] On Behalf Of
bobeasy1 at comcast.net
Sent: Thursday, August 16, 2007 8:20 AM
To: arid_gardener at Ag.arizona.edu
Subject: [Arid_gardener] Question from Home-Hort WWW page


Bob
85742
bobeasy1 at comcast.net

We had a 25-ft mesquite go down in a freak tornado-like disturbance. It was
a beautiful tree and sat directly in front of our house in our small yard. 

We're looking to replace it, but are concerned that another mesquite might
suffer the same fate.(The roots stay pretty near the surface, drinking off
the drip system.)

Is there a way of planting another mesquite whereby the roots wold run
deeper? Or if too problematic, is there another good-looking tree we could
substitute that would tolerate freakish winds better?

Thnks for your help! 


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