The
dangers of pruning
MEXICAN FAN PALMS Washingtonia robusta
While a striking tree when peeled and pruned, they can be
one of the most dangerous trees to maintain
when they grow to above 35 feet. Every year climbers are killed
in Southern California when the
Mexican Fan palms they are pruning slough, trapping them beneath
hundreds of pounds
of fronds, suffocating the climber in as little as 20 minutes.
How does this happen?
Above 30‑35 feet the fibers that hold
the frond to the trunk go thru a form of abscission. This
process seperates the frond from the trunk allowing the
“bag” or accumulation of dead fronds to slide
and fall off the trunk (as seen in the photo to the right).
However, below this height, the fronds remain persistent
and never fall off. This bag of persistent fronds keeps
the non-persistent fronds from falling (this can also
be seen in the adjacent palm and is evidenced by the swelling
of fronds below the freshly peeled portion of upper trunk).
As the climber removes the persistent fronds from the
bottom up he comes to the spot where the "loose bag"
of non-persistent fronds no longer has enough support
to keep it from falling. It slides down the trunk, trapping
and pinning the climber with hundreds of pounds of weight.
He cannot breath. If he cannot free himself quickly, he
dies of suffocation.
In the lower right photo (a blow up of the left photo) the
frond seperation can be seen. These fronds come loose and slip
down into the next set of fronds, becoming very compact and resistant
to breaking apart and falling off. This "bag" has become
a latent trap, waiting until the fronds beneath are removed and
then sliding down the trunk.
The safest way to prune these are with an aerial lift. If
access does not permit, there are new
and safer techniques than climbing under the bag of dead fronds.
Does your tree service
have an aerial lift? Does your tree service know how to safely
prune these? Do they carry
worker's compensation insurance
in case of an accident? Or will you be left holding the "bag"?
For
more information call (619)
443-1775
Fax (619) 443-3324
