Ancient Bristlecone Pine Forest Soil, Vegetation, and Bedrock Mapping
In this half-day field exercise, students hike the Discovery Trail at the Ancient Bristlecone Pine Forest (USDA Forest Service) to observe the relationships between geologic (rock and soil), geomorphic (aspect), and ecologic (vegetation) characteristics in the area. Using their field observations, they subsequently create a simple field map illustrating changes in vegetation, soils, and bedrock.
- Compare and contrast soil characteristics at different study sites in the field area.
- Qualitatively assess vegetation types, abundances, and densities at different study sites in the field area.
- Compare and contrast bedrock lithologies at different study sites in the field area.
- Create an annotated field map using a line drawing to illustrate relationships between soils, bedrock, and vegetation in the field area.
Higher Order Thinking Skills Goals:
- If applicable, determine relationships between bedrock geology, soils, and vegetation, using data collected in the field.
Other Skills Goals for this Activity:
- Gain experience in locating oneself with a simplified trail map.
- Practice systematic note-taking.
Context for Use
This activity was completed during the 2-week summer E-STEM Field Course with ~20 undergraduate students interested in environmental science.
Prerequisite Skills and Concepts:
In the first cohort of E-STEM students, some students had experience with describing soils. In the second cohort, all students had this experience. All students had completed a variety of botany observations and botanical transects prior to beginning this activity. Students had varying levels of experience with rock identification.
How the Activity is Situated in the Course:
View the E-STEM field course timeline for more information about how this activity is situated in the course.
Description and Teaching Materials
In the field:
- As they hike, students select at least 6 study sites and mark each study site on their line drawing.
- Each study site should include field notes on the following: soil composition, thickness, color, size of grains; elevation of study site compared to other parts of the trail; steepness of slope of study site compared to other parts of the trail; relative vegetation density (high, medium, low, absent); aspect; vegetation types; presence or absence of Bristlecone Pines; type of bedrock (carbonate or siliciclastic.)
- Students should mark the location of the contact between different bedrock units.
- Students should either add to their existing field map or make an office copy of their map (in their field notebook) with a legend and other necessary components of a field notebook entry per the field notes rubric.
Teaching Notes and Tips
- To set the stage, we began with a student presentation about Bristlecone Pines (as part of the field presentation activity) and some basic plant identification from the botany faculty member (especially distinguishing between the Limber Pine and Bristlecone Pine.) Students were then instructed to make a line drawing of the Discovery Trail using the kiosk at the trailhead.
- The Discovery Trail is an approximately 1 mile loop trail and is moderately strenuous, primarily owing to the elevation (over 10,000') and lack of shade. Students should hike the trail in a counter-clockwise direction.
- It helps to encourage students to work in small teams and have faculty and TAs roving on the trail to check student field notebooks for accuracy of their study site locations and thoroughness of field site descriptions. Some students who do not have extensive rock identification experience may need assistance initially distinguishing between the carbonate and siliciclastic units that crop out along the trail. More advanced students might wish to observe a third, less abundant bedrock unit that crops out just before the final downhill back to the visitor's center.
- Bathrooms and interpretive exhibits are available at the visitor's center.
Assess this activity with the rubric used for the Field Notes Badge.