Experimental plot sites showing 1 meter ground surface contours and the locations of the terrestrial light detection and ranging scanning, TLS, meteorological towers, and snow pits as well as the associated elevation, slope, aspect, and plot areas for the a. above tree line site and b. near tree line site. c. The ground-penetrating radar unit is shown being towed behind the user on skis and d. an example post processed radar gram for 45 meters of the near tree line survey transect. The figure is courtesy of the author, R. Webb.