A standard method of expressing the girth of a living tree is "diameter at breast height" (DBH). It is the diameter of a tree measured at an average height of 4.6 ft.
One of the largest measured DBHs ever recorded belongs to a giant sequoia in California dubbed the General Grant tree. It is located in Kings Canyon National Park. Its DBH was measured at a whopping 29 ft. Imagine you want to tie a ribbon around the General Grant tree. How much ribbon will you need? You need to know the circumference of the tree to estimate the amount of ribbon.
To calculate circumference, you know to use the equation for the circumference of a circle with π (pi)= 3.14 and d = ft. The circumference (C), rounded to the nearest foot, is ft.