The ornamental design for a treestand, as shown and described.
FIG. 1 is a perspective view of a tree stand showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an enlarged view of an encircled portion labeled, “FIG. 8,” in FIG. 1.
The dashed dot lines represent the unclaimed boundary of the enlarged portion view of FIG. 8 in FIG. 1 and FIG. 8. All even dashed broken lines represent unclaimed subject matter and form no part of the claimed design.