As it stands, the oak tree is an oak tree. If, however, we were to pluck out all of the leaves of this oak tree, would it still be a tree? Most people would definitely say yes. Trees lose their leaves in the winter all the time yet still remain trees. Suppose now that we were to saw off a few branches. Would our tree still remain a tree? Most people, again, would respond in the affirmative. We have all seen trees without a few branches. But let us say that we were to take another step and cut off all of the branches. What would we be left with? Now the response we would most likely get would be a trunk on a root, definitely not a tree. The point of this analogy is to illustrate that once any existent is subjected to thorough analysis, we soon realise that its nature is not fixed and determinate. In the case of the tree, this becomes clear when we ask: exactly when in our process of sawing off the branches does the tree stop being a tree? The difficulty in pin-pointing a universal essence which we can unequivocally identify as “treeness” is one reason for believing there is no such essence to begin with.
— Sacred Web (Volume 23, p. 51 – Atif Khalil – Emptiness, Identity and Interpenetration in Hua-yen Buddhism