Suppose george washington completely removed the bark from around the base of a cherry tree but was stopped by his father before cutting the tree down. the leaves retained their normal appearance for several weeks, but the tree eventually died. the tissue(s) that george left functional was (were) the

Hi! 

What George Washington did was called "Girdling"

It consists of removing bark, cambium, and phloem from a tree, and leaving only the xylem and heartwood functional. 

What it does to the tree is to remove the tissue that is responsible for carrying the sugar from the leaves to the roots. This causes the roots to die, and with them, the tree dies too. This process is very slow and is used by horticulturists to kill trees while giving the environment time to adjust.