At the upper elevations of Saguaro National Park, aspen and Chihuahua pine persist under starkly different ecological strategies - one moisture-dependent, the other adapted to fire and drought. This presentation draws on tree-ring data and climate-driven growth simulations to examine how these species have responded to past climate variability and what their trajectories may look like under hotter, drier conditions. The results reveal patterns of species-specific resilience and provide actionable insight for climate-adaptive management in this iconic desert sky island.