Lab Overviews
Lab 1. Launching an Expedition
In Lab 1, students will be introduced to the science of dendrochronology. They will see how tree-core samples are obtained and processed, and take a virtual tour of a tree-ring laboratory. Then they can watch videos of two accomplished dendrochronologists who describe their career paths, the role serendipity has played in their careers, and their advice to students interested in pursuing science. Students consider what types of special trees dendrochronologists seek to help them answer questions about how our climate has changed in the past. Students then explore the tree-ring datasets available from the International Tree-Ring Databank (ITRDB), a public archive of tree-ring data, and focus on the work of one of the science investigators, and his/her peer-reviewed research, to help them understand the nature of science.
Time required: 90 minutes
Tools and Materials Needed:
Lab 2. Humpty Dumpty Talus Slope and Drought in the Hudson Valley, NY
In Lab 2, students will go on a virtual expedition to study drought in the Hudson Valley using some of the same tools and analytical procedures that tree-ring scientists use. They will explore the Humpty Dumpty talus slope site in Google Maps and learn about the importance of picking study sites where the ecology of the site shows that the trees will be sensitive to climate. Students will learn to evaluate patterns in tree-ring records by observing and comparing core samples. They'll also use Climate Explorer, a powerful online tool that enables them to map and evaluate recorded meteorological data. They will confirm that tree-rings are recording climate information by comparing their analysis of tree-ring data and observations of 'marker years' from the core samples to the recorded data from Climate Explorer from the same year.
Time required: 180 minutes
Tools and Materials Needed:
Lab 3. Tree Rings and the Ancestral People of Pueblo Bonito: Uncovering the Past
In Lab 3 students will go on a virtual expedition to New Mexico and visit Pueblo Bonito, an ancient ruin that was inhabited between 750 and 1250 AD by Ancestral Pueblo people. They will explore the region with Google Maps and search for samples of wood to analyze. They then will use a qualitative method to create a skeleton plot from the scanned image of a sample of Western Juniper and use it to date the Pueblo Bonito site. In Part 3, students use ImageJ, a public domain image processing program developed by the National Institutes of Health to produce a graph of their skeleton plot, and combine it with sections produced by their classmates to determine how the climate of Pueblo Bonito changed in the past. Did an extreme period of drought force the Ancient Puebloans to leave the site? In Part 4, they investigate a long-term data set produced by tree ring records to identify the existence of mega droughts and other drastic climate changes that affected the people of Pueblo Bonito.
Time required: 180 minutes
Tools and Materials Needed:
Lab 4. Sharing a River: The Colorado River Story
In Lab 4, students will travel to the Colorado River Basin and examine tree-ring data from three sites in New Mexico. In Part 1, students will take a journey down the Colorado River to give them perspective on the scope of the watershed and how various stakeholders draw water from the river to serve the needs of seven western states. Students will then collect data on where the water comes from, who is using the water and how much is being used, and what the future may hold for people living in the basin. In Part 2, students will work in small groups to explore aspects of the Colorado River Basin using a variety of resources and tools such as Google Maps. They will learn about the environment and ecology of the region they are studying and the context for collecting tree-ring cores to analyze stream flow and moisture conditions of the basin. In the second part of the activity, they will focus their attention on one of three regions in New Mexico, examining the terrain and looking for trees that might yield core samples with a long-growth history. In Part 3, students will work in small groups and use a quantitative method to measure the width of tree rings (using ImageJ) to produce a graph of tree growth for the Colorado River basin over the past 120 years. Then they will compare their results with the published tree-ring records from the same sites, and evaluate a two thousand year tree-ring based streamflow reconstruction for the Colorado River to determine how often major droughts occur.
Time required: 180 minutes
Tools and Materials Needed:
Lab 5. Warming in the Northern Hemisphere: Reconstructing Temperature
In Lab 5, students will visit several sites in the northern latitudes, or boreal forests, to gather clues about how temperature has changed through time. Initially, they will investigate the tree-ring datasets available from the International Tree-Ring Databank (ITRDB) and then focus on the work of one of the science investigator's peer-reviewed research to help them understand the nature of science. They will explore three different tree-ring research sites in key egions across the globe using Google Maps in order to understand the ecological conditions that make these trees reliable recorders of climate. In Parts 3 and 4, they will use a quantitative method to measure the rings to produce a time-series graph of a tree-ring core sample. They will then combine their measurements with those of their classmates to produce a preliminary tree-ring record, compare their records with a published millennial length tree-ring temperature reconstruction, and identify and evaluate the potential cause of extreme events found in that reconstruction.
Time required: 180 minutes
Tools and Materials Needed: Computer access for all parts of the lab