Hi Folks,

I have a large live oak that splits into 4 main branches at the top of the
trunk. In the middle of the top of the trunk is a 1-2 gallon sized cavity.
Debris had been building in the cavity and several plants were growing in
the dirt and humis in the cavity. So I cleaned out the leaves and dirt and
pulled the plants out.

Now, I have this pit in the tree that holds at least a gallon of water. In
this part of Florida, that is a huge mosquito breeding ground. I've read
that fillers and sealers are a bad a idea. And that I shouldn't drill a
hole to allow the water to drain.

So, I wonder if anyone can suggest the best way to avoid the stagnant water
retention in the tree cavity.

Thanks very much,

Jack Coletti
St. Petersburg, FL

On Mon, 20 Jun 2005 03:37:47 GMT, "MostlyH2O"
wrote:
(snip)
Now, I have this pit in the tree that holds at least a gallon of water. In
this part of Florida, that is a huge mosquito breeding ground. I've read
that fillers and sealers are a bad a idea. And that I shouldn't drill a
hole to allow the water to drain.

So, I wonder if anyone can suggest the best way to avoid the stagnant water
retention in the tree cavity.

Thanks very much,

Jack Coletti
St. Petersburg, FL

Good on you for doing your homework. It is true that filling cavities
and/or draining them are discredited practices. Some arborists I've
run across have tried covering the opening with wire mesh, then
coating that with a weatherproof coating. Others have filled cavities
with self-expanding foam (like for house insulation). I'm not sure
either one is very helpful, but neither is likely to be harmful.

Your best bet is probably to accept the fact of water in the cavity.
If wood is constantly exposed to water, it won't decay. Decay is an
aerobic activity, so it is the constant drying/wetting cycle that
takes its toll.

As for the mosquitoes, go to the hardware store and check out the
insecticides aisle. You should be able to find mosquito dunks. These
are small disks of bacteria which kill the mosquito larva while being
pretty harmless otherwise. Toss one into the cavity and forget it
until you see it has lost effectiveness (sorry, no idea how long one
dunk will last before you need a new one).

Keith Babberney
ISA Certified Arborist

replying to MostlyH2O, presence wrote:

Plant a fern, moss, or elephant ear in the hole... depending on size. The
plant will self sanitize the situation; out-competing mold and fungus and
generally suck the moisture out of the cavity.






for a larger hole plant a bush... or even another tree

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