Undergraduate Honors Theses

Thesis Defended

Spring 2017

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Environmental Studies

First Advisor

Joel Hartter

Second Advisor

Eve-Lyn Hinckley

Third Advisor

Dale Miller

Abstract

Climate change is increasing the frequency and severity of fires, especially in the Western United States, making it pertinent that tree regeneration rates and causes are understood. The goal of this research is to assess the impacts of post-fire environments on seedling regeneration in dry conifer forest of eastern Oregon’s Blue Mountain Ecoregion. Specifically, I seek to determine whether soil properties determine successful seedling recruitment. In the summer of 2016, sixty-eight soil samples from across four different fires in the Blue Mountain Ecoregion were collected to analyze for total carbon, total nitrogen, and pH. The soil variables were compared with additional independent variables of fire severity and slope aspect. Over 16 to 20 years after the fire, north-facing sites and low burn severity sites had more seedlings than south-facing and high burn severity sites. Significant differences were found between seedling counts and soil properties, though older seedlings were found more often in soils with lower pH. These findings will be useful to forest managers who seek to determine the microsite conditions that promote natural post-fire conifer regeneration.

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