Bordeaux mixture is simple: 10 lbs lime, 10 lbs copper sulfate, 100 gallons water. Often used as a fungicide on grapes.

I was thinking of spraying it on pine and spruce trees, but substitute potassium alumininum sulfate (Alum) for all or part of the copper sulfate.

Here's my thinking:

Copper sulfate is an acidic salt so tastes very sour. Alum is very very very bitter. Lime is white, and helps bind the salts to the tree. (It comes off with several rains)

So now I have a compund that reduces sun warming/drying in winter, and makes the tree taste terrible to deer and mooose. Anyone done this?

(Please do NOT come back and tell me about any way to make my trees taste bad that involves anything that costs more than 2 cents per tree to make. I have 15,000 trees.)