Department of Geography

PEOPLE

Dr. Paul Knapp, Professor

At McKenzie Pass, Oregon, September 2006 en route to core western juniper trees with colleague, Dr. Peter Soulé (right) of Appalachian State University.

While I have long appreciated the field of dendrochronology, it was not until the mid-1990s that I became actively involved.  Prior, my geography interests were in biogeography and climatology and thus working with tree-rings allowed me to combine my interests.  My first project involved studying western juniper expansion in my home state of Oregon.  Ironically, I have distinct recollections of collecting western juniper firewood while on camping trips in the 1960s and 70s in central Oregon.  Little did I know that two decades later I would have a different appreciation of the value of the tree!  Since then, I have been principally involved with a series of dendroecological projects that have focused on the role of atmospheric CO₂ fertilization affecting radial growth rates of western juniper and ponderosa pine, dendroclimatology projects that have examined spatio-temporal patterns of droughts, and the reconstruction of severe wind events.  I have collected tree-ring data in a variety of places in the American West, and always look forward to my next field adventure.  Each year, I try to fund students to help with these projects, and I am grateful for their help over the years.  My observations over the past decade have led me to believe that tree-ring science is a great sub-discipline for physical geographers, with extensive, relevant, and timely applications that are often interdisciplinary.  In the section on projects, some of these applications are listed.

Jason Ortegren, M.A. 2004
Ph.D. student

August 2005.  Jason Ortegren in southwestern Montana standing in front of a 350-year old ponderosa pine.

My academic interests have centered on weather and climate since I took my first physical geography course as an undergraduate.  My research to date, including my first publication has focused on climatic variability at the urban/environmental interface, specifically the urban heat island and its long-term manifestations.  My interest in dendroecology was sparked by the arrival of Dr. Knapp at UNCG in 2005.  He employed me as a field research assistant during the summers of 2005 and 2006 where we collected ponderosa pine samples from remote areas in Montana, Idaho, and Utah.  The confluence of three of my favorite things—climatology, trees, and wilderness—made for an easy decision to alter my career research path in the direction of dendroclimatology.  See “Current Projects” for a brief description of my dissertation research.

William Tyminski, M.S. 2005
Ph.D. student

Bill Tyminski examines cores in the lab.

I was born and raised in the beautiful Nutmeg State (Connecticut).  Growing up I was forever intrigued with the details of the living and physical world and would later pursue this interest academically.  I received a B.S. in Biology from Eastern Connecticut State University (ECSU) and then headed south to Georgia State University (GSU) for my M.S. in Biology.  As a master’s student, I spent the first half of my degree working in the lab of Dr. Delon Barfuss, where I looked at basolateral transport of amino acids across the proximal tubule of the nephron.  I then spent the second half working as a research assistant for Dr. Robbie Smith, a coral reef ecologist who studies the rates of recruitment and survival of juvenile corals, and how they vary over time in the Florida Keys.  It was through this direct exposure that I began observing the changes to ecosystems in response to climate change.  I then decided to pursue the cause rather than the effect of these changes. In addition to my Biology courses at GSU, I took several Geography courses.  It was here that I was introduced to dendrochronology and Dr. Knapp.  I am currently a Ph.D. student in the department of Geography at UNCG and pleased to call the Carolina Tree-Ring Science Laboratory home. 

Nicholas Crawford, B.A. 2003
 M.A. student

Central Utah, June 2006.  Nick Crawford finishes coring a ponderosa pine.

I grew up in Franklin, a small town in southwestern North Carolina.  My collegiate career began at Southwestern Community College (SCC) in Sylva, NC.  While at SCC I took all the courses offered in Geography and Biology.  I transferred to UNC-Greensboro where I majored in Geography with a minor in Environmental Studies.  Going to graduate school I was interested in research on climate and the environment.  As a graduate student I was able to take courses with Dr. Paul Knapp learning how dendrochronology can be used to research past climate.  Additionally, I was a field assistant for Dr. Knapp in Utah for the summer of 2006. After the Utah trip I decided to focus my graduate research in dendrochronology. I find this area of research interesting and rewarding because it combines my three main research interests: climate, biology, and the environment. 

PROJECTS

Dr. Knapp

Current Research:

1) Anomalous 20th century ponderosa pine growth and potential CO₂  fertilization in naturally-occurring stands in the interior West, USA.  Funded by the USDA NRI Competitive Grant Program--Plant Adaptations to the Environment. This project, a collaborative effort with Dr. Peter T. Soulé of Appalachian State University, has involved dendroecological field work in Washington, Oregon, northern California, Idaho, Montana, and Utah to collect samples of ponderosa pine from a variety of environmental settings. We have published our findings from the PNW sites in the journal, New Phytologist (2006) vol. 171, pp. 379-390.

To minimize the influence of confounding factors on tree growth such as fire suppression, logging, air pollution etc.., we selected trees growing in park-like stands and on Federally-protected sites such as research natural areas (RNAs).   Above:  ponderosa pine growing on the Upper Sand Creek RNA in central Utah, June 2006.

Steve Shelly (right), the RNA coordinator for Region 1 of the USFS and UNCG graduate student Jason Ortegren at Ferry’s Landing RNA in northern Montana, August, 2005.  This is another example of a park-like stand of ponderosa pine.

2006 Utah Fieldwork Team: (L-R) Dr. Paul Knapp, Andi Cochran, Jessica Brannock, Dr. Peter Soulé, Jason Ortegren, and Nick Crawford.  

2) The Occurrence of Severe Pacific Northwest Windstorms: A Multi-Century Dendroclimatic Assessment of their Ecological Impacts. This is a collaborative research project with Dr. Keith Hadley of Portland State University.  Hurricane force winds from powerful mid-latitude storms affect much of the westside forests of the Pacific Northwest causing severe windthrow.  Some trees, however, survive multiple high wind events, yet the central stem is snapped, altering the growth of the tree and creating a unique tree-ring growth signature.   By identifying this growth signature, Dr. Hadley and I are working to reconstruct the frequency of these storms during the past 300+ years.

 

Windthrow of old-growth noble fir on Marys Peak, Oregon.

At Marys Peak, Oregon, Keith Hadley and students from Portland State University examine a noble fir snapped by a wind event.

Keith Hadley inspects a noble fir that was recently wind-snapped by a windstorm on Marys Peak, Oregon.  If this tree survives, the unique growth ring pattern beginning post-event will make it possible to date the wind storm event.

Current Research--Graduate Students:

Jason Ortegren:  Spatial and temporal patterns of historic drought in the Piedmont reconstructed from tree-ring data.  Aside from the main goal of a reliable paleoclimatic reconstruction in an area of rapid population growth, I plan to contribute at least four original chronologies to the existing network; the Piedmont is currently underrepresented in the national tree-ring data grid.  One site we have selected for sampling is in the Uwharrie Mountains of central North Carolina.

 

The rocky soils of the Uwharrie Mountains of central North Carolina precluded extensive agriculture during the past century.  Thus, stands of old-growth hardwoods exist.
                    

Bill Tyminski: Reconstruction of plant hardiness zones using tree-ring chronologies from the Southeastern US.  Recent alterations to the plant hardiness zone boundaries are one of several changes to ecosystems affected by the current warming trend.  These zones represent the likely success or failure of ornamental trees and shrubs, and are generally constructed using the average annual minimum temperature at a particular site.  Therefore, warming would shift these zone boundaries expanding the range of plants adapted to warmer climates.  This project will focus on the reconstruction of historical plant hardiness zones and evaluate the temporal changes of these zones. 

Nicholas Crawford: Using tree ring analysis to examine differential response to environmental controls for multiple species in the North Carolina Piedmont.   My research is in its early stages.  I hope to be able to determine how trees in North Carolina are responding to climate change and compare the responses between species.  This research has a wide range of benefits because trees are important in so many different ways. 

  The wood preparation room contains sanders, saws, work benches and other items necessary to prepare the cores for measurement.

The crossdating room contains several stations for crossdating samples.

The measurement room houses two workstations.

Map cabinets serve as storage for the cores.

Graduate students have their own workspaces in the lab.

An old juniper near Prineville, Oregon.  Because of their limited commercial value, old-growth juniper woodlands are common in the interior Pacific Northwest. 

In the fall of 2002, a severe cold spell affected many western juniper trees in central Oregon.  Dr. Peter Soule’ and I studied the geographical extent of the freeze-affected trees and linked this to topoedaphic conditions.

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