Tree growth occurs in three places--
At the twig tips and root tips (meristem) and around the outside of the
trunk, branches, and roots (cambium).
The meristem region of tissue expansion or tree growth is at the tips of
both twigs and roots. This is unspecialized tissue that can form wood,
buds, or flowers. Each year, trees will lengthen twigs and roots,
produce flowers and fruit, and grow new buds.
As another poster has already noted, most of the bulk a tree trunk,
branch, or root is dead wood. The living part is only a narrow of
regenerating tissue (the cambium layer). Cambium produces new wood on
its inside and new bark on its outside. The cambium grows only from the
inside out, not up or down the length of a trunk, branch, or root.
Each year the cambium produces two distinct rings of tissue. In the
spring, a layer of thinner-walled cells are grown. In the summer, a
layer of thicker-celled, sometimes larger cells are grown. The layers
are called "springwood" and "summerwood," respectively.
There's much on tree physiology at the Forest Products Laboratory web
site as well as wood characteristics, drying, usage, etc., etc., etc., ...
I've had a decorative thermometer screwed to a beautiful Silver Maple
Something like this:
I've also still got the bracket I used to use to raise and lower a
bird feeder years ago still screwed to same tree.
Based on how many leaves I rake - and remove from my gutters - each
year, I don't think I've hurt the tree too much. ;-)
Besides, it's standard practice to "cable" a tree to keep it from
splitting. A couple of screws or bolts isn't going to hurt an
otherwise healthy tree.
Wrap the tree with whatever that stuff is at the garden shop; looks like
cardboard, and use spring-loaded clamps to hold up the lamp.
But don't penetrate the tree - it's like ringing the dinner bell for
diseases and parasites.
In a previous home on a heavily wooded lot in Ohio, we had a lot of
landscape lighting installed in the trees, as well as brackets to
hang bug-zappers. All the mounts were firmly screwed into the wood
of the trees. The trees remained healthy, and actually began growing
around the mounting brackets.
~~ If there's a nit to pick, some nitwit will pick it. ~~
Heh, perhaps a repair that fixed what wadn't broke......
rcm is far from an irrelevant newsgroup. ahr would be well served
crossposting a variety of content over there, as that group has a most
inneresting blend of a wide variety of pro's, diy-ers, and just generally
smart problem solvers.
Many on rcm will know more about certain specifics of a problem than yer fav
contractor, altho they might not have the same overall skill level over the
AND, if for some reason the thread IS hijacked, most often it will be a very
intelligent hijack. :)
Not knockin yer intent, just sayin said intent may have been a little
AND, not sayin rcm is "better" than ahr -- each has slightly different and
most often very useful perspectives converging on a problem.
An arborist told me to use stainless hanger bolts. Screw it into the tree and
leave 2-3 inches sticking out. Thread a nut on only enough to add your
whatever and another nut. This leaves plenty of space for the tree to grow
in diameter before it hits the first nut. This also doesn't disturb the seal
tree made around the screw by having to back it out on an annual basis.
I've had several dozen stainless steel eyes and screws in the oak
trees around my house for decades. The wood grows tightly around the
metal so I use minimum 5/16" eyes which are strong enough to not break
when backed out every few years. I hang things from the eyes with
shackles rather than fastening them tightly to the tree so it can grow
My firewood had assorted plain and galvanized screws and nails in it.
Sometimes plain steel nails stayed tight, sometimes the bark opened up
around it to leave a wound. Quarter inch and smaller screws often
break off when I remove them.
No objections to any of that, other than that if the tree grows very fast
and the homeowner forgets about it, it may cause more trouble than my way.
When it reaches the first nut, the bark has already engulfed the hex part
of the bolt. So the bolt cannot be backed out, and the light would need
to be rehung on new bolts. Depending on the tree, this could happen many
decades later, or just a few years later.
firstname.lastname@example.org (Una) fired this volley in
So... Oh, well! If it's completely engulfed by new growth, it won't be a
problem for the tree.
It might become a problem for the poor sap who runs that lumber through a
surface planer 100 years from now. <G>
I looked pretty closely at the stuff in Williamsburg. Almost without
exception, it's not hanger bolts, it's lag bolts. I suspect they just
check them periodically for "engulfment", and adjust them. All in all,
that wouldn't be too often per tree. They'd just have to have a PM
Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:
Yes, but the new bolts will require new penetrations, each with a small
but non-zero risk of injury to the tree.
Yes. I think that's the decision point for the OP. If scheduled PM is
the norm, go for lag bolts. If set-it-and-forget-it is more the norm,
go for hanger bolts. Given these lights will be 20 feet up, I'd favor
hanger bolts (long ones).
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