Portable tree step
FIG. 1 is a perspective view of a portable tree step showing our new design; 
     FIG. 2 is an opposite side perspective view thereof; 
     FIG. 3 is an enlarged top plan view thereof; 
     FIG. 4 is an enlarged side elevational view thereof with the opposite side being a mirror image thereof; 
     FIG. 5 is an enlarged bottom plan view thereof; 
     FIG. 6 is an enlarged front elevational view thereof; and, 
     FIG. 7 is an enlarged rear elevational view thereof. 
     The broken line showing of a hook member if FIGS. 1 and 2 is for illustrative purposes only and forms no part of the claimed design.