White pine blister rust (WPBR) has been affecting New Hampshire’s white pines for more than a century, yet no data exist on the long-term effects of the non-native disease on the state’s forests, particularly with respect to the regeneration and sustainability of white pine, and forest succession. This study aimed to address the gaps in the literature by exploring: 1) the current distribution, incidence, and severity of WPBR in New Hampshire; 2) the application of two historical hazard ratings models, one climatic, and one biotic; and 3) the long-term effects of the disease on forest composition, structure, and succession. Historical blister rust maps were used to select research sites for a comparison between pine stands that had blister rust, and pine stands that were infection-free when mapped (1929-1976) by the NH Blister Rust Control Program. One hundred sites in 50 towns were revisited in the spring of 2018. This research included the development and application of: 1) a WPBR canker severity index for white pine; 2) a disease-disturbance model for WPBR; and 3) a forest succession trajectory for forests disturbed by WPBR. Results suggested that 1) WPBR incidence had increased since a 1998 statewide study; 2) native Ribes populations were well-distributed throughout the state; 3) Ribes that infected white pines were less likely to be within the historical 300-yard protection zone; 4) the historical hazard models were outdated, particularly in relation to New Hampshire’s climate; and 5) WPBR can aid natural successional processes to influence forest structure and succession. This research connected historical data with the present to improve our understanding of the relationship between WPBR and forest succession in a changing climate. During this process, several knowledge gaps were identified for future research
