Many of the Junipers sold on Zen Garden Bonsai are wearing wire to encourage growth in a certain shape. If you have on one of these trees there are a few things you should know.
Wire cannot stay on forever, usually it can stay for about 6 months, but that depends on the time of year. For example in the winter, the tree isn't doing a lot of growing so it will take longer for the diameter of the branch that has been wired to expand enough to create a problem. In the spring and early fall ( September-October) many trees are in active growth, so you need to check the wire more frequently.
Regardless of what I might have planned, this is your tree now, if you don't like the shape/style, change it. Just don't make really big moves on a thick branch without checking out several videos about wiring. Bend the wire, not the branch and first, study the branch carefully to identify the weak spots ( like the crotch) where careless bending might induce a break.
If wire cuts into the bark of a deciduous tree- like an Elm or Fukien Tea, it will leave a permanent scar- not good. With evergreens like the Juniper, it's not such a big issue because as they mature the bark gets rougher and can quite effectively hide the scars.
Heavy, structural wire - Cut the wire at short, regular intervals so it more or less drops off the tree. You'll need wire cutters with a rounded head. Like this:
If you have the right cutter, don't hesitate to use it to remove medium or even fine wire. If the wire has already started to cut into the branch, unwinding the wire can easily break the branch, so again - cut the wire. You can't reuse it anyway.
If for some reason you MUST remove by unwinding- be careful. As you unwind the wire, be sure to also support the wire and the branch with your other hand so that through the entire operation you are putting the least possible pressure in any one direction.