Mount Mujil is an ancient volcano which is located in Kulon Progo district with elevation of 265 msl. Currently this area is mostly overgrown by various vegetations, in which one of them is tree strata vegetation. Researches regarding the vegetation has not been done quite much. Hence, this research aims to understand the tree strata vegetation types with the highest and lowest Important Value Index (IV), determining the variety of tree strata vegetation types, understanding the correlation between measured abiotic environment condition to the stand grouping pattern of the tree strata vegetation, determining the potential of the research result as a learning source for biology subject in first grade of senior high school in ecosystem-level biodiversity subject. The data sampling in this research used plotless method such as Point Centered Quarter. To understand the diversity index (H'),Shanon-Wienner Index was used, and to understand the correlation between the measured abiotic environment conditions against the stand grouping pattern, cluster analysis was used. The research result is discussed to see whether this research has potentials to be used as a learning source for biology subject in accordance to the learning source criteria. The research result shows that there are 18 tree strata vegetation types in every study area with Tectona grandis as the highest IV(126.48%) and Ficus septica has the lowest INP (0.22%). The diversity index of the tree strata vegetation types is relatively low. H'ranges around 0.49-0.85. The abiotic environmental conditions which are related to the stand grouping pattern aresoil moisture, soil pH, and light intensity. The discussion regarding the research process and result fulfill the criteria to be a learning source for biology subject in first grade of senior high school in ecosystem-level biodiversity material.