I have searched and can not find a definitive answer.
Does anyone know why Galvanized wire is not recommended for styling trees. Is is just the annealing of the copper/aluminum process that makes it better to manipulate or is their a chemical/atomic reaction between the galvanized coating that is harmful to the tree. Galvanized wire is so much more cost effective/readily available and it bends good enough to not hurt the tree, so there must be another reason. I have only read that you should not use galvanized, but no astounding reasoning other than pliability.

As far as I know the main reason for not using galvanised wire is the proximity of the zinc coating to the tree which could be harmful. I don't know if this is actually true, but for the amounts used by non commercial growers the cheapness of galvanised wire should not really be an issue. I use copper salvaged from spare electrical cable when I can get it, or plastic coated garden wire for thinner branches.

Dave

"Galvanized steel will also corrode and release high levels of zinc into the soil. Plastic covered steel is Ok but it is very springy in smaller callipers and does not hold the tree so well, it also has a tendency to break. Thicker sizes are very stiff and hard to twist together"

www.kaizenbonsai.com/bonsai-tree-care-in...-to-repotting-bonsai

parker wrote:

Is is just the annealing of the copper/aluminum process that makes it better to manipulate or is their a chemical/atomic reaction between the galvanized coating that is harmful to the tree.

The very reactive metal zinc will dissolve and be washed off with general watering, flushing high levels of zinc into the soil. The major change from high levels of zinc is in the nuclei of root tip cells. The chromatin material becomes highly condensed and some of the cortical cells show disruption and dilation of nuclear membrane in presence of 7.5 mM zinc. The cytoplasm becomes structureless, disintegration of cell organelles and the development of vacuoles will also occur. The number of nucleoli also increase in response to zinc resulting in the synthesis of new protein involved in heavy metal tolerance.

So, yeah. Bad stuff.

Ed

Wow, thank you all. very informative and educational.

Okay, here's the source:

link.springer.com/chapter/10.1007/978-90-481-2666-8_53#page-1

Ed

BonsaiLearner wrote:

parker wrote:

Is is just the annealing of the copper/aluminum process that makes it better to manipulate or is their a chemical/atomic reaction between the galvanized coating that is harmful to the tree.

The very reactive metal zinc will dissolve and be washed off with general watering, flushing high levels of zinc into the soil. The major change from high levels of zinc is in the nuclei of root tip cells. The chromatin material becomes highly condensed and some of the cortical cells show disruption and dilation of nuclear membrane in presence of 7.5 mM zinc. The cytoplasm becomes structureless, disintegration of cell organelles and the development of vacuoles will also occur. The number of nucleoli also increase in response to zinc resulting in the synthesis of new protein involved in heavy metal tolerance.

Somehow I doubt they were talking about leaching of zinc from wire into the soil. It reads like they are talking mine tailings, considering the concentrations.
Galvanized steel is used in a wde reange of gardening applications without any bad effects.

To me, the morelogical reason would be that the zing coating breaks, and rust ssets in, leaving stains on the bark.

7.5mMol of zinc has a mass of around 4.9035g.
For a wire of diameter 4mm (chosen at random), the minimum coating is 500g per square meter, so, as 1m^2 = 10000cm^2, 500g per 10000 square centimeters which is 5g per 100 square centimeters. Divide 100 by two then times by five to make the thickness 4mm and the required length of wire is less than 2.5m.

It's possible is what I'm saying

Ed

source of galvanization figures:
www.azom.com/article.aspx?ArticleID=1852

But, yes, the rust staining is probably a more likely issue.

BonsaiLearner wrote:

But, yes, the rust staining is probably a more likely issue.

But, the whole point of Galvanizing metal is to prevent rust. The zinc coating is very rust resistant.