Copper vs aluminiun

Not to hijack Tony's thread I started this one:

I have heard not to use copper wire in pots: and

not to use copper on certain species. I know some frugal bonsaiist reserve their copper for pines, etc... But I have never heard it being "bad" for specific species.

Will the folks that made these observation care to elaborate a little more on them, I am curious?

The second one is me - I've read in more than one book that prunus species are sensitive to copper wire. That's why I asked Tony what his experience was, as the subject had already been raised as it were. I prefer copper but have always used Aluminium on my cherries etc, so I was curious about whether it was true or not.

I use cupper on conifers and aluminium on decidious trees.

I'll give you a hint: If the books don't say WHY it is dangerous, it probably means the authors don't know. And that probably means this is another of those silly bonsai myths rooted in TRADITION!

I've heard that copper conducts cold into the tree and damages it. I've also heard that copper conducts summer heat into the tree and damages it. Either would be nonsense.

I've also head that copper ions "leach" out of the copper and damage the tree/soil. In theory, that could be possible -- In Florida, aquatic scientists routinely use copper sulfate to kill off algae blooms in ponds and lakes, and to clear stream and lake bottoms of growths of noxious aquatic weeds (Hydrilla) (incidentally killing almost everything else in the process) -- but seems to me to be unlikely. Trees aren't single cell plants or grasses with thin cell walls; the bark would "insulate" the living tissue from any leachate from the wire -- which wouldn't do any measurable "leaching" in any event.

But, to throw more cold water on the theory, copper -- in small amounts -- is one of the micronutrients that plants need for good health.

Of course since most of my trees are the smaller size I don't use copper wire, anyway.

Thanks for NOT hi jacking my thread Rick.

I have enough issues with growing bonsai in my garden and do not believe that a minute amount of copper will in any way upset the growth of this tree.

But for the record... I usually used aluminum on the branches of deciduous trees.

Thanks, Dorothy.

I'll repeat what I've said for a very long time: Don't rely on bonsai books for horticultural information. You can learn to wire, prune and do other "bonsai" things from a bonsai book, but when they try to tell you what makes plants grow or not grow. or what to do about bugs or disease, or fertilizers, go somewhere else.

Interesting observations!

In the past I have heard of folks that use copper on conifers and aluminium for deciduous etc... but these observations were more based on cost (keep the best for the best) so to speak, vice that one or the other would be harmful to trees.

I've also read wrt unwire trees prior to winter (especially copper ones) as they transmit cold??? I prefer wiring my trees late fall early winter as I get extra set and go the extra mile for me, and have not lost trees due to heat transfer.

We had a copper induction system in our sea water intakes on the ship. It precluded mussel growth from forming up in cooling systems (eventually blocking them). The system was extremely effective and it was said no harm to the environment, with the exception of sterilizing the mussels.

Rick
Copper is a commonly used poison for marine invertebrates. I believe it is part of the oxygen carrying molecule in their blood although I don't know how that relates to its toxicity. Marine aquarists will use copper solutions to treat infestations of parasites on fish, but if the tank includes decorative inverts (crabs, shrimp, corals, etc) they will also be killed. I've heard of copper spikes being used as herbicides but don't think the effect is related, and I'm not sure I believe that it would actually work.

Conducting heat and cold should have little impact on the trees. The wire is not going to get any hotter or colder than it's surrounding environment, nor will the tree wrapped in that wire. Perception is deceiving here. A piece of wire will feel colder to touch in the winter than a piece of wood at the same temperature because the wire conducts heat away from your hand more quickly. Nonetheless the wood and wire are the same temperature. Just to be sure the point is thoroughly dead, if you took two trees - one wrapped in wire and another bare - at room temperature and put them both into a refrigerator, the wired one will cool down a little faster, but both trees will end up at the same temperature as the inside of the refrigerator.

My understanding of the preference of aluminum over copper for deciduous trees is due to aluminum being less stiff, thereby reducing the chance that you will snap a typically more brittle deciduous branch when bending it.

I too heard that copper wire will kill a tree in the cold winter season. Then about 20 years ago one of my students who was a professor at Cornell University did a controlled experiment to see if the copper wire stayed cold and would kill twigs on deciduous species. He actually measured the temperature of the bark under the copper wire and where the areas without wire.

Guess what the results showed? Copper wire on bonsai during the winter actually INSULATED the tree. The bark temperature under the wire was higher than the unwired areas. I never would have thought that!

As Jim said, you cannot rely on bonsai books for accurate horticultural information as most of the authors do not have an educated horticultural background. "Urban Myths" run abound in the bonsai community.

Bill

Well that is interesting indeed Bill. When you think of it in another fashion, it does insulate the bark somewhat.