Climate and Geomorphic Influences on Ponderosa Pine Regeneration, Prescott Arizona

Abstract:

Global climate change is creating notable responses in the structure and dynamics of the forest
ecosystem. Patterns observed include high tree mortality and changing radial growth patterns in
dry southwestern United States. Ponderosa pine (Pinus ponderosa) is one of the dominant tree
species of the southwest woodland, and research on its regeneration in response to climate
change is lacking. The prior research studying the area's regeneration found that pine species are
not regenerating as quickly as other species. Ponderosa pine forests form in drier, warmer
environmental conditions, creating scattered stands in the region. These stands are highly
susceptible to rapid regime change influenced by wildfire, climate warming, and drought.
Therefore, we investigated the regeneration and establishment of Ponderosa pine in Prescott
National Forest, Arizona. Study plots were established in relation to mature tree height.
Regeneration in previous studies has been found at two tree lengths away from mature
individuals (Davis et. al. 2019). The median year of germination was 2014. We found a
significant correlation between germination year and August’s PDSI (wettest month for the study
area). This means PDSI has influenced the germination of Ponderosa pine. Findings from this
study will help forest managers and USFS to manage the changing southwestern woodland.

Keywords: Regeneration, Ponderosa Pine, Climate Change, PDSI

Authors: