Funnily enough I just covered that with @creativetruth. Yes, I have baby apricot trees so will give this a try on them. Need to figure out how to neatly break these magnets in half so they can be removed when the tree has bushed out.
Sorry to hear about your cherry trees, but exciting times for the new ones! Do you have magnetised cables next to them? This and basalt seem like the simplest and most effective ways to improve growth.
Some have cables next to them others don't. The ones that don't are on the direct pathway to my grain fields where tractors drive in and out. This is why I'm interested in a say more "mobile /above the ground" solution such as the round magnets you experimented with.