Anicdotal evidance has shown that burlap and wire can cause problems in the root system. University studies are being done prove this through scientific method.
They say the basket will rust, but we are digging up artifacts from the revelutionary war. Burpal decays, but I've dug up 5 year old plants that have partialy decayed burlap on them. They will say that it is natural, untreated fiber. I say why risk it.
What you should do is dig down beside the ball so you can get at the backing material. Cut the burrlap off as low as possible, and cut the baskett with some heavy wire cutters, as low as possible.
ensure that the flair where trunk and roots transition is exposed to air, I prefer to jave the firs order roots partialy exposed too.
If you are realy interested in the trees well being, dig down into the ball to inspect the root system, look for roots that encircle the ball and the straighten them out into the lawn, bury them in slit trenches, a few inches down. now you have increased the area the tree gan get water from and ahev given it a head start in establishing itself.
Lastly do not use any spol dirt on thop of the root ball, this will just increase the chance of SGR's later in life.