according to given information, let's draw a rough sketch of the tree and the ground.
In the attached picture AD is tree
DB is the root.
BC is the span of tree root.
Given that the total length of the tree from root tip to top is 23 feet so
AB= 23 ft
Given that tree's root is 9 feet below ground, so DB=9 ft
Given that spans a radius of 6 feet, so BC= 6 ft
we have to find the tree's elevation above ground, which means find the value of AD.
From picture, we see that
AB=AD+DB
plug the given values
23=AD+9
23-9=AD
14=AD
Hence final answer is 14 ft.