Kemper, Lauren (2022) Short interval wildfires and post-fire resilience in interior Alaska. Masters thesis, Northern Arizona University.
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Kemper_2022_short_interval_wildfires_post-fire_resilience_interior_ala.pdf - Published Version Restricted to Repository staff only Download (1MB) | Request a copy |
Abstract
Nearly one third of global forest carbon stocks are stored in boreal forests, and as the climate warms and dries, wildfire frequency and severity in the circumpolar region are increasing. These changing fire regimes and their effects on boreal forest structure may significantly impact carbon pools and fluxes, and therefore climate feedbacks. Within this framework, identifying the conditions where ecological resilience may be lost is vital. The conifer dominated boreal forests of western North America have historically had high resilience to wildfire, but as the frequency of fires increases, this resilience is threatened. Recent studies have found evidence of shifts in species dominance from conifer to deciduous and a loss of compositional resilience as a result of increased fire severity or shortened fire return intervals. This study aimed to determine how changing fire return intervals affect post-fire stand dynamics, specifically seedling recruitment, across a gradient of fire severity and soil moisture conditions within Interior Alaskan boreal forests. We found that changing fire regimes, namely shortened fire return intervals, alter post-fire seedling recruitment patterns, leading to a shift in species composition towards deciduous dominance post-fire in many previously conifer dominated stands. The differences observed in conifer and deciduous regeneration between short and long interval plots confirm the idea that shortened fire return intervals in boreal forests will result in a shift in dominance from conifer dominated to deciduous dominated forests if these post-fire densities remain steady as the stands mature. Our study also provides evidence that seed availability and, to a lesser extent, seedbed quality, can affect patterns of seedling recruitment in stands that burn at shorter fire return intervals. Interactions with environmental factors such as soil moisture may amplify the effects of shortened fire return intervals on species dominance. This research contributes to mounting evidence that the increase in the frequency of disturbance events can fundamentally alter boreal forest stand dynamics, leading to the loss of compositional resilience. The rate of short interval wildfires is increasing in northwestern boreal forests, so it is imperative that we continue to study the effects of changing fire regimes on boreal forest resilience to understand the broader impacts on climate feedbacks.
Item Type: | Thesis (Masters) |
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Publisher’s Statement: | © Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author. |
Keywords: | Forest files--Alaska; Boreal forests--Alaska; Carbon sequestration--Alaska; Climate change; |
Subjects: | Q Science > QK Botany |
NAU Depositing Author Academic Status: | Student |
Department/Unit: | Graduate College > Theses and Dissertations College of the Environment, Forestry, and Natural Sciences > Biological Sciences |
Date Deposited: | 22 May 2023 21:12 |
Last Modified: | 22 May 2023 21:12 |
URI: | https://openknowledge.nau.edu/id/eprint/5891 |
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