Here’s my 2 cents on this issue. To me, the most important thing
is to remove the twine holding the burlap on the root ball. In my
30 years in horticulture, I’ve seen too many trees planted without
the twine removed. In a few years after the trunk has grown around
the twine, the tree is susceptible to breaking at that point in the wind.
Here is a link to a pdf on burlap and twine, etc. that shows on the 11th
page what can happen when the twine is not removed.

http://blog.lib.umn.edu/umtrees/trees/MnDOT%20Landscape%20Class%202012.pdf