Despite a considerable effort of scientific community and a huge amount of literature, the capacity to assess and monitor biodiversity at coarser spatial scales in short time periods is still limited. Thus assessing indicator or surrogate information from existing data sets, such as forest inventories, is a challenge for biodiversity management and monitoring. We used two forest data sets (woody plants and all vascular plants) to test whether the diversity of woody plant species can be used as predictor of the diversity of all vascular plant species. Our study was performed in the forests of Liguria, Italy.