At the end of September you will want to begin wrapping the trunks of young trees from the ground up to the first branch.
Trees left unwrapped are at risk of becoming damaged by deer rubbing against the trunk, rabbits munching off the outer layer of bark (also known as girdling) or sunscald.
There are different types of protectors that you can use such as plastic tubes or a paper wrap.
If using the plastic tubes, be sure to use white tubes rather the black to prevent the plastic overheating and damaging the trunk.
Wraps can come off your tree as early as April, but try not to leave them on longer than May so the trunk can get airflow and sunlight. There are certain wraps that are designed with holes which are able to be left on year round.