Your English is fairly good.
However, I think you mean magnetic field not electromagnetic field.
I don't think it is possible since, to induce a current into the wire, you would need a closed circuit.
Normally the globes in Xmas tree lights are in series.
Therefore you would have to short circuit the wires at the power plug. So if you induce a current into the loop to make the globes glow, it would only work if all globes were intact. If any globe was faulty, no globes would glow thus negating the point of the exercise.