Source: The Great Interpretation of Dreams (Ibn Sirin)
Cutting the root of a tree in a dream indicates abandoning religion, moving from a country, or cutting family ties.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Cutting the root indicates the severing of one's origin or sustenance.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Cutting the root is interpreted as worry and calamity concerning one's origin and lineage.