The ornamental design for a lighted treeskirt, as shown and described.
FIG. 1 is a perspective view of a lighted tree skirt, showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The even dashed broken lines of a Christmas Tree in FIG. 1 depict environmental structure and form no part of the claimed design. The dot-dashed lines represent thread stitching and are part of the claimed design.