Spatial structure of alpine treeline plays a key role in its response to climate change, yet the processes that are responsible for creating that structure are poorly understood. Here, we describe a treeline on the west side of Pikes Peak with different tools to gain insight of the structure at a local scale and to investigate the potential endogenous mechanisms that appear to influence it. We hypothesized that the trees will be clustered in the system through positive intraspecific interactions and that the treeline is a potential phase transition system with classical criticality. With the classical description of treeline structure, we divided the zone into different sections of increasing elevation range with the assumption that the mechanisms driving the structure of each are the same, and ran Ripley’s K function for cluster analyses. Ripley’s K function showed significant tree clustering through the sections in the study area, especially between the elevation of 3600m and 3680m. Clustering among large-sized trees were significant across the entire treeline. To examine the potential of the treeline as phase transitions, which allows us to treat the system as continuous rather than in sections, we analyzed presence of fractal structure in the treeline. Analysis of the spatial structure reveals significant fractal geometry in size classes, as well as on the edges of big tree clusters which has the potential to evolve into a percolation cluster. The analyses show evidences that the system could more likely be in robust criticality rather than phase transition. This study provides insights into describing the treeline on a local scale and could contribute to the current study of treeline dynamics and treeline as a complex system.