Can this tree stand in the middle of a room?

No. It is a half tree with a flat back, so it is meant to go against a wall or in a corner. From the front it looks like a full tree; from behind it is bare.

How wide is it and how much space does it need?

The face is 33 inches wide and 6.5 ft tall. Because it is half-round, it projects only about half that depth from the wall, so it fits where a full round tree would not.

Are the lights included and replaceable?

Yes, the tree comes pre-strung with lights. If a bulb fails, check the bulbs and connections along the strand; the lights are wired to the tree rather than removable strands.

PVC branches with a green finish and transparent light covers. PVC is durable and holds ornaments, but it looks less natural than polyethylene-molded tips.

How do I store it in the off-season?

The half shape folds and packs into a narrower footprint than a full tree. Store it in a cool, dry place and reshape the branches when you set it up again.

Is a half tree worth it over a full tree?

If the tree will always face the room from a wall, a half tree gives the same front view with less floor space and less setup. If you need to see it from all sides, choose a full round tree.