Tree species manifest a wide range of life histories. The simple trajectory of a seed sprouting and then growing vertically in a continuous fashion as a single stem to become a canopy tree is often the exception rather than the rule in forests. Many species of trees sprout repeatedly in their lifespan or spread horizontally through root suckers. Sprouting allows trees to hold a place in the forest understory, allowing for persistence through disturbances such as drought and recruitment of new stems during other disturbance such as fire. We use demographic techniques in long-term plots coupled with population modelling to study how tree populations respond to a variety of biotic and abiotic factors over time including: introduced pathogens, deer browse and isolation resulting from sea-level rise. We are particularly interesting in understanding the causal factors associated with regeneration failure in tree populations.