We claim the ornamental design for a lighted tree ornament, as shown and described.
FIG. 1 is a perspective view of a lighted tree ornament, showing our new design, in a used condition with a tree shown in broken lines;
FIG. 2 is a front elevation view of the lighted tree ornament;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken lines showing the environment in FIG. 1, and the broken lines showing the light bulb in FIG. 6, are for illustration purposes only, and form no part of the claimed design.