Identifying secret graves through forensic botany is considered a relatively simple application of the field, roughly at a Level 1.5.
It doesn't require the identification of specific plants, but rather a knowledge of how certain plants will quickly root in freshly disturbed soil, with new seeds germinating until a balance is reestablished—a process that often takes decades.
On one hand, vegetation in the disturbed area is at a different stage of growth compared to the surrounding environment; on the other hand, the composition and distribution of the new plants differ from the original plant community.
Furthermore, a buried body could chemically alter the soil, either fostering or inhibiting plant growth, or promoting the growth of some plants while suppressing others.
