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Harvard Forest REU Symposium Abstract 2022
- Title: March of the Oak: Influences of Eastern Hemlock Decline on Red Oak Seedling Mortality
- Author: Aiyana T Vazquez (Wellesley College)
- Abstract:
Persistent human interference and climate change are exposing tree species to new vulnerabilities and driving seedling migrations; however, the effect that pest invasions have on soil pH and on the success of migratory seedlings is not well understood. Changes to forest composition, especially due to increased pest infestations, like the introduction of Hemlock Woolly Adelgid on Tsuga canadensis (Eastern Hemlock) in northeastern temperate forests can disrupt soil quality regulation. Additionally, as the climate warms, seedlings like Quercus rubra (red oak) are migrating northwards where they encounter varying light and soil conditions impacting its success. We compare two Long Term Ecological Research (LTER) sites, Harvard Forest in Petersham, MA, and Hubbard Brook in Campton, NH, to examine (1) how seedling survival rates differ between the two sites with obverse hemlock presence; and (2) what stress, if any, does soil acidity and light availability apply on seedling survival. As a foundational species, T. canadensis, is an important regulator for soil, light, and heat in the understory. By using seedling census data collected from plots where seedlings were tagged and identified, we analyzed data to focus on plots with at least one red oak seedling, as well as selected plots with diverse hemlock presence, to sample soil pH. We expected that increasing presence of hemlock creates a more acidic soil environment and restricts incoming light, which may negatively impact the survival of red oak seedlings. This study can help improve our understanding of seedling mortality and its role in predicting future forest recovery.
- Research Category: Biodiversity Studies; Ecological Informatics and Modelling; Group Projects; Invasive Plants, Pests & Pathogens; Large Experiments and Permanent Plot Studies; Physiological Ecology, Population Dynamics, and Species Interactions
