North American Fruit Explorers mailing list at ibiblio

[Mark Lee <mark.lee.phd@gmail.com>]

This past year something stripped most of the fruit from my trees just
days before from my planned harvest dates. I think multiple critters were
responsible for the fruit theft, including squirrels, rats, raccons and
possums. I did some research today getting ideas on how to protect my trees
next year. I found these helpful instructions on a GardenWeb post from 2008
for installing an "electric fence" right on the trunk of trees. I would be
interested in hearing from anyone with experience with such a system
-Mark Lee, Seattle


http://forums2.gardenweb.com/forums/load/fruit/msg0715493511722.html

Electric fence on fruit trees.
Both squirrels and raccoons are a problem for me. Squirrels stripped my 2
plum trees of fruit in days, most apples disappeared, raccoons broke a
young apple tree by climbing it. For the last 5-6 years, the electric fence
has kept the varmints out. I set up the fence when my plums are showing
some color, keep it going until apples have been picked. One year I
disconnected it while grandkids were visiting and forgot for 2-3 days, and
every plum disappeared.
I use a fence charger that Fleet Farm used to sell (about $ 18), meant to
keep dogs and cats out . They may still have it, or any other low-priced
unit will do. The idea is to keep the varmints from climbing up the trunk
of the tree.
I wrap the trunk of every tree with wire mesh (hardware cloth), from ground
up to about 2 ft. high, this will be the ground terminal. Connect a wire
from from the cloth to a large nail stuck in the ground. Run a wire from
the ground terminal of the charger to the nail. You only need this charger
wire on one tree, the others will connect through the ground.
The charger hot terminal connects to a spiral of galvanized wire (16 or 18
gauge) around the trunk, with turns about 6 inches apart and spaced about 3
inches above the wire mesh with insulators. The idea is to have the hot
wire high enough above the mesh so the squirrel cannot just jump over it,
but low enough so it cannot climb under it.
The spirals need to be insulated from the ground mesh. I made the
insulators by cutting ½ ‘ wide pieces of 3" plastic pipe, then cutting the
circles in half. A hole drilled at each end of the half-circle, one hole
for the wire, other for the nail that attaches it to the tree. I suspect
there are better ways to make the insulators.
An insulated wire connects from the hot spiral to the hot (red) terminal of
the fence charger. I run this wire to the nearest tree, then from there to
the next tree, keeping wire about 2 feet above the ground. If it touches
the ground, it will short out quickly, unless the insulation is very heavy
duty, like 1000 volt rating. The charger voltage is quite high (several
hundred volts) , but limited to very low current for safety. This means
that a human would get a unpleasant shock, but not enough to injure (or be
unable to let go). I did find a red squirrel dead under the hot wire once,
apparently it was not safe for him.
My fence charger sits outside, under a 5 gallon bucket (with a heavy rock
on top). I check every few days to make sure the setup is still working,
bought a cheap tester (about $ $ 2-3).
- h.teder, Jul 31, 08