Growth release of subcanopy trees following Mountain Pine Beetle induced overstory
mortality in Rocky Mountain National Park
PROPOSED RESEARCH PROJECT
Christopher Deaderick
Dr. Daniel Tinker
Department of Botany
Introduction
For the past decade, mountain pine beetles
(MPB) have invaded millions of hectares of
forest in Colorado and Wyoming, causing
extensive conifer mortality. While it is commonly
believed that growth rates of subcanopy trees
increase following removal of overstory trees,
limited empirical data exist to confirm this. Tree
ring data can provide insights into such growth
releases, as well as chronological occurrence of
past climate and disturbance events and the
severity and frequency of these events.
Purpose Statement
This study will examine the magnitude of growth
release of subcanopy trees following MPBinduced overstory mortality, and will estimate the
differences in growth release among cohorts
(vertical canopy layers) and among tree species.
Hypothesis
I hypothesize that there will be an increase in
subcanopy growth as a result of decreased
overstory cover and reduced competition for
water, light and nutrients as a result of extensive
mortality among mature trees.
Importance of Study
By elucidating the growth response of subcanopy
trees, this study will enhance understanding of
important alterations in stand structure and
composition following severe MPB forest
mortality.
The Mummy Range from Moraine Park, Rocky Mountain National Park
Methods
The study area is located in Rocky Mountain National Park (RMNP) west of the Continental Divide in
Lodgepole pine dominated forest severely impacted by MPB. In 2008 the MPB epidemic appeared to
be subsiding during field surveys.
Thirty-eight sites will be resampled, each containing two 20 m x 20 m square plots randomly
positioned 90 m apart, for a total of 76 plots. In each plot tree core samples and tree diameter (DBH)
will be collected for 5 trees of each canopy cohort and species type. Collecting densiometer
measurements will estimate tree canopy cover.
Tree core preparation and analysis will follow standard dendrochronological methods (Stokes and
Smiley 1996). Tree ring crossdating matches the growth patterns of narrow and wide rings across the
sampled trees to show past regional environmental factors that produce common year-to-year radial
growth variations. This study will identify the timing and magnitude of growth release events detected
from tree ring widths.
Relationship between wildfire synchrony, precipitation
anomaly, and seedling establishment in the Black Hills,
South Dakota (Brown 2006).
Range of the mountain pine beetle
in North America
Acknowledgements
Dr. Daniel Tinker
Gregory Pappas
McNair Scholars Program