Graduate students Alicia Gray and Kereen Griffith spent a chunk of this 2013 summer conducting their master's thesis research in Soquel Demonstration State Forest, California. In collaboration with CalFire and with the help of Clyde Elliott (current geography undergraduate student) and Amanda Gleason (recent graduate of our undergraduate program), the students set off to study global environmental changes in this monumental coastal redwood forest ecosystem.

Photo 1: The team in California. From left to right: Kereen Griffith (M.S. Candidate in geography), Amanda Gleason (UNT geography graduate), Alicia Gray (M.S. Candidate in geography), and Clyde Elliott (UNT undergraduate student).

Global environmental change refers to human activities on Earth that have global-scale impacts (e.g., climate change), as well as to simultaneously occurring local changes (e.g., deforestation) that can, but don't always, have a global-scale impact. There are many global environmental changes, and Alicia and Kereen are studying two of them: exotic forest pathogens and increasing atmospheric deposition (e.g. the deposition of nutrients and pollutants to Earth in rain, fog, or dust).

In California's coastal redwood forest, Phytophthora ramorum (commonly referred to as Sudden Oak Death or SOD) is a relatively recent exotic pathogen that is currently threatening Pacific coastal forests in the western United States. According to the 2012 USDA Forest Service annual aerial survey, the number of dead trees in California's SOD-impacted areas increased nearly 10-fold from 38,000 to 376,000, while the geographic extent of tree mortality increased nearly 7-fold from 3,238 to 21,853 ha between 2011 and 2012. Alicia's research aims to understand how different habitat types and light transmittance affect spatial patterns of two major host species of the pathogen. Understanding where the hosts are most prevalent is important for knowing where the disease impacts are likely to be greatest.

Photo 2: Alicia climbs a tree to take a leaf sample for species identification.

Photo 3: Alicia measures solar radiation in a clearing in Soquel Demonstration State Forest, California.

California's coastal redwood forest may also be affected by decreasing air quality in major cities such as San Francisco and San Jose. How? What goes up into our atmosphere must come back down to the Earth's surface, and it often does, even long distances from the source. In the California Bay Area, nutrients and pollutants emitted in growing urban areas can be deposited to coastal redwood forests in downwind mountain areas. Where does the material fall? Which areas will be hardest hit? Kereen's research examines how topography and forest characteristics affect where nutrients and pollutants are deposited in the coastal redwood forest. Her research is important for identifying species and areas at risk of increasing nutrient/pollutant deposition.

Photo 4: Kereen uses a laser range finder to measure a Douglas fir tree in Soquel Demonstration State Forest, California.

Photo 5: Kereen cleans her collectors in the forest with the help of Clyde Elliott.

Both Alicia and Kereen are combining fieldwork and laboratory work with Geographic Information Systems and/or remote sensing to answer fundamental questions about our changing Earth. This research was conducted with the support of Ed Orre, Angela Bernheisel, Julie, and Ana. Thank you CalFire!

Want to be prepared to tackle problems related to our changing planet?

Come join us at UNT Geography.