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2016 Undergraduate Research Fellows

Meet the 2016 Undergraduate Research Fellows and view this year’s Center for Tree Science Undergraduate Research Symposium.

 

Mackenzie Coden, Undergraduate Research Fellow in 2016
Mackenzie Coden

Northwestern University

Title: Testing protocols for preserving oak leaf tissue and extracting DNA for use in oak conservation genetic studies

Advisor: Dr. Sean Hoban

Funding provided by: Center for Tree Science

Mackenzie's Blog Posts

Mackenzie's Poster: PDF iconTesting-protocols-for-preserving-oak-leaf-tissue-and-extracting-DNA.pdf

Abstract: Quercus havardii (Fagaceae) is unique in that it primarily reproduces clonally and hybridizes readily with related species. Human disturbances in its native southwestern American range are causing rapid population declines. It is important to assess current amounts of genetic variation and determine the most effective management options to prevent further population loss. To study Q. havardii genes, first the DNA must be isolated. It is difficult to extract DNA from oaks because they contain compounds that interfere with the extraction process. Q. havardii provides additional challenges due to physical properties. This study determines which combination(s) of field preservation techniques, leaf homogenization, and DNA extraction protocols yields the largest amounts of high quality DNA. I performed a full-factorial comparison of these factors on Q. havardii and two other white oak species. I found that conditions such as chilling leaf tissue rather than drying the material, and extracting with a classic CTAB protocol rather than an extraction kit yielded higher DNA quantities. Homogenizing material with a machine yielded higher DNA concentrations than hand grinding, but at a lower quality. Further study needs to be performed to assess the purity of the DNA samples before the optimum protocol can be confirmed, but already the results have been applied to field collection and will be applied to future work on Q. havardii.

 

Alison McGarigal, Undergraduate Research Fellow in 2016
Alison McGarigal

Colorado College

Title: Comparing the Efficiency and Accuracy of a Digital Photography and Laser Based Technique in Conducting Forest Surveys

Advisor: Dr. Chuck Cannon

Funding provided by: Center for Tree Science

Ali's Blog Posts

Ali's Poster: PDF iconComparing a Digital Photography and Laser-Based Technique in-Conducting Forest Surveys (PDF) 

Abstract: Human activity is changing forest structure and composition globally, particularly through drought, fire, intensive land use, and climate change. To understand these effects, we must document current forests comprehensively so that changes can be objectively measured. Although remote sensing technologies reveal the distribution and type of forests, we have limited detailed knowledge of forest structure and composition. Traditional methods of collecting this data, using tape measures and compasses, require substantial human effort and field time. Adopting new technology in forest surveys facilitate larger, more frequent, and more informative surveys to gain a more refined understanding of forest response to change. The present study compares two new technologies, digital photography (Photopoint) and hand-held laser devices (Laser), to traditional forest survey methods in their efficiency and accuracy.  We found that the Photopoint method is the most time efficient (p<0.05). This advantage increased substantially with larger sample areas and the number of trees sampled (p<0.05). The Laser method did not improve survey efficiency (p=0.799) and the error rate, both in accuracy of tree diameter measurements and in missing small trees near the plot margins, was higher than the traditional method (p<0.05). These errors could be due to inaccurate distance measurements, occlusion due to vegetation coverage, and human error. While final results for the PhotoPoint method’s measurement accuracy are not yet available, the detailed panoramic images produced capture a wealth of incidental data that will be useful for monitoring and understanding forest structure and composition change.

 

Quinn Taylor, Undergraduate Research Fellow in 2016
Quinn Taylor

University of San Diego

Title: Burn Forest Burn: Effects of Annual Burning of Forest Soils

Advisor: Dr. Meghan Midgley

Funding provided by: Center for Tree Science

Quinn's Blog Posts

Quinn's Poster: PDF iconEffects-of-Annual-Burning-of-Forest-Soils.pdf

Abstract: In eastern deciduous forests, controlled burning is a common management technique used to control invasive understory plants and promote oak regeneration. However, little is known about how burning impacts soils. Studying these effects will aid in better understanding how burning is affecting the forest as a whole. We evaluated soil biogeochemical responses to controlled burning in forest plots with varying abundance of two types of trees: trees associated with either arbuscular mycorrhizal fungi or ectomycorrhizal fungi. We addressed two main questions: (1) Does soil biogeochemistry change with controlled burning? (2) Does tree mycorrhizal association mediate the effects of annual burning on soils? We found that burned areas have higher pH, carbon, nitrogen, and organic matter, and decreased acid phosphatase activity. Tree mycorrhizal association was not found to impact soil factors or to mediate the effects of burning. We predict an increase in phosphorous in burned areas, which may cause an increase in phosphorous-rich plants. Burning increases light available on the forest floor and increases organic matter, carbon, and nitrogen, which may benefit oak regeneration. However, increased understory herbaceous plants in the burned areas are likely shading out many of the oak seedlings. These results should be considered when predicting the benefits of controlled burns.

 

Kirsten Triller Undergraduate Research Fellow in 2016
Kirsten Triller

University of Northwestern-St Paul

Title: Environmental impact and influence on urban tree health of biochar and biosolids

Advisor: Dr. Bryant Scharenbroch

Funding provided by: Center for Tree Science

Kirsten's Blog Posts

Kirsten's Poster: PDF iconEnvironmental-impact-and-influence-on-urban-tree-health-of-biochar-and-biosolids.pdf

Abstract: Biosolids (BS) and biochar (BC) are two soil amendments that have been used to remedy urban soils, which often have poor water and nutrient retention due to anthropogenic influence. BS have been shown to greatly encourage tree health, but they have also contributed to nutrient leaching.  BC, in contrast to biosolids, may slightly contribute to tree health, but it also has considerable potential to promote a healthy environment. The goal of this research was to find a soil amendment, or combination of soil amendments, that would both promote tree health and have a positive environmental impact. The effects of BS, BC, BS+BC and a control (null) were studied in three soil types and two soil coverings. A “healthy environment” was quantified by measuring nitrate and phosphate leaching, soil respiration, and volumetric water content. A “healthy tree” was quantified by measuring chlorophyll concentration, leaf area, primary and secondary growth, and crown fullness. Overall, our BS had a more negative environmental impact than BC and null (significantly more nitrate leaching, phosphate leaching, and soil respiration) while contributing positively toward tree health in some ways (increased relative diameter growth and chlorophyll concentration). Consistent between BC alone and combined with BS, our BC neither significantly contributed to nor suppressed any negative environmental impacts, and it did not significantly contribute to tree health. Many factors influence the function of biochar as a soil amendment, including the biochar feedstock, pyrolysis procedure, postproduction handling, and application rate. Although this biochar did not appear to influence environmental health or juvenile tree health, future studies should continue to explore the many variables that impact the function of different biochars. Once the effects of these variables are recognized, biochar may become a dependable soil amendment for encouraging tree and environmental health.

 

Kasey Pham, 2016 URF student
Kasey Pham

Michigan State University

Title: A time and place for everything: The shifting predictors of genetic diversity in the oak chloroplast

Advisor: Dr. Andrew Hipp

Funding provided by:  The National Science Foundation - Research Experiences for Undergraduates

Kasey's Blog Posts

Abstract: Oaks are a tricky genus of trees.  We learn in high school biology that a group of living things can only be considered a species if they can breed and produce offspring.  This definition of a species is based off of the assumption that different species will have different enough DNA that they will be physically incompatible with each other, and will not be able to breed.  Oaks defy these rules entirely.  While different oak species have distinctly different DNA, they can still interbreed.  In more scientific terms, breeding between species is called hybridization.  Despite how common and well-known oaks are, only in the last fifty or sixty years have scientists begun to tease apart the ways that these trees behave reproductively.  If we can understand how oaks behave with regards to their mating habits, we will be better equipped to study them in ecology, conservation, and in commercial settings.  Our study seeks to add to that understanding by looking at patterns of oak hybridization using DNA from the oak chloroplast and nucleus.  Because of the different mechanisms for passing on their genes, chloroplast DNA gives us a history of recent hybridization in oaks, while nucleus DNA gives us an older history of oak evolution.  In addition, the closer the proximity of two oaks, the easier it is for them to hybridize.  Using chloroplast and nuclear DNA sequences, as well as latitude and longitude data for the oaks those sequences belong to, we are studying the differences in chloroplast DNA.  Our goal is to understand how evolutionary history and geographic location contribute to these differences.