PS 44-165 - Long-term demographics and matrix models indicate Quercus montana population decline

Wednesday, August 9, 2017
Exhibit Hall, Oregon Convention Center


Callie Oldfield, University of Georgia; Jonathan P. Evans, University of the South; Sarah Oldfield, University of the South


Quercus montana (chestnut oak) is a dominant tree in xeric ridge habitat of the eastern United States. It has been predicted that Q. montana populations may be able to remain stable in the face of a changing climate. To examine population-level trends in demography, Q. montana trees were tracked in one hectare of forest on the Cumberland Plateau, Tennessee from 2000-2015. Trees were categorized into size classes, and demographic data were used to parameterize a discrete size-classified population projection matrix. Using this matrix, the population was projected 100 years into the future.


Over the study period, we found an increase in the number of individuals in the smallest size class (0.5–1 meter height) and a decline in pole-sized individuals (1–4 meter height). Of the 456 individuals alive in 2000, 49.8% were in the same size class in 2015, 17.5% were smaller, 5.0% were bigger, and 27.6% were dead. The total number of individuals in the population increased by 12%. The population projection indicated a general downward trend in all size classes. These results suggest that this foundational xeric oak may be on the decline as it faces environmental changes including fire suppression and climate change.