Date of Award
2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Natural Resources
First Advisor
Anthony W. D'Amato
Abstract
Fire suppression and disconnection from historic fire regimes has a distinct and significant impact on fire-dependent natural communities, changing community structure, composition, and diversity, as well as fuel availability. Novel stressors facilitated by climate change have the potential to further degrade fire-dependent natural communities and impact their restoration. The long history of fire suppression, disconnection from cultural fire regimes, and the recent range expansion of Southern Pine Beetle (Dendroctonus frontalis) present substantial and imminent challenges to the restoration and maintenance of pitch pine barrens, a rare (G2), endemic, fire-dependent natural community found in the northeast US. This research sought to elucidate the response of pitch pine (Pinus rigida) regeneration and impacts to the species diversity and abundance of understory plant communities resulting from four regionally common restoration treatments (harvest, fall prescribed fire, spring prescribed fire, and mowing followed by prescribed fire) in pitch pine barrens across four states (Maine, Massachusetts, New Hampshire, and New York).
Pitch pine small seeding abundance demonstrated a negative relationship with average leaf litter depth, total understory cover, and abundance of shrub oak (Quercus ilicifolia and Q. prinoides) seedlings across sites and restoration treatments. All treatment types had significantly more pitch pine seedlings than untreated control sites. Large seedling abundance followed a similar trend and was negatively associated with increased leaf litter depth. Sapling abundance showed a positive relationship with the proportion of overstory basal area occupied by pitch pine and a negative relationship with shrub oak sapling abundance. Collectively, these findings reflect previously established conditions for pitch pine regeneration including exposed mineral soil, reduced leaf litter presence, reduced shrub oak cover, and the proportion of mature pitch pine in the overstory. No single management strategy emerged as most effective, although higher severity disturbances appear to be more successful at the establishment of pitch pine regeneration.
Distinct understory community assemblages and structures were associated with different restoration strategies. This included a higher abundance of species that can endure fire and resprout from buried plant parts in prescribed fire units, whereas fire-sensitive species and those slow to recolonize after fire events were most abundant in control units. Restoration treatments also generated unique understory structural conditions related to treatment severity and frequency, including greater shrub densities important for supporting several threatened wildlife species. These findings demonstrate how imperative it is to reinstate disturbance events in pitch pine barrens to restore desired conditions and support cultural and ecological objectives.
Language
en
Number of Pages
103 p.
Recommended Citation
Stutzman, Kathleen Anna, "Tree regeneration dynamics and understory plant community response in northeast pitch pine barrens under a range of restoration scenarios" (2024). Graduate College Dissertations and Theses. 1959.
https://scholarworks.uvm.edu/graddis/1959
Included in
Ecology and Evolutionary Biology Commons, Forest Sciences Commons, Natural Resources Management and Policy Commons