The researchers behind this project compiled data from museums, botanical gardens, agricultural centers, and other sources to conclude that there are currently 60,065 tree species known to science. These include Abarema abbottii, a rare and poorly understood tree native to China and Kyrgyzstan, and Zygophyllum kaschgaricum, a vulnerable limestone-bound tree found only in the Dominican Republic. The Global Tree Assessment, which aims to assess the conservation status of all of the world's tree species by 2020, is the next step in this field of research.