To explain where treeline occurs on a global scale, it is first valuable to identify those environmental variables that

[answerhappygod]

To explain where treeline occurs on a global scale, it is firstvaluable to identify those environmental variables that are mostsimilar across treeline locations. These variables could influencethe biological mechanisms behind treeline formation andmaintenance.
You will examine the treeline in three locations on the globalscale using Google Earth:
Fly to the above-mentioned three National Parks in Google Earth,and select a site of your interest where treeline occurs, Zoom into an appropriate eye altitude (represents ASL, Above Sea Level),and you will see pictures like Figure 2(C).
PLEASE PROPER PICS ON GOOGLE EARTH PRO AND COORDS!!