Lab 2 - Humpty Dumpty and Drought in the Hudson Valley, NY

Download a Student Activity Worksheet here. (Microsoft Word 2007 (.docx) 60kB Mar13 19)

Introduction

This tree-ring science expedition takes you to a fascinating landscape in New York State. The Shawangunk Ridge, which includes Mohonk Preserve and nearby Minnewaska State Park, is a remarkable natural area. Glacially-sculpted sandstone ridges result in an incredible and unique landscape. A rich human history and many outdoor activities await visitors. This region, often referred to as "The Gunks," is also renowned for rock climbing, hiking, and biking.

In one area, a talus rock fragments that have accumulated at the base of a cliff or slope slope made of giant sandstone and conglomerate boulders is home to a forest of hemlock trees that have been growing since the 1600s. Because the terrain is so rocky and the trees so difficult to access, these trees were never logged or destroyed by fire. Most of the old trees in the US northeast were cut long ago for fuel or cleared to make room for agriculture. More recently, invasive woolly adelgids small aphid-like insects that suck the sap from young twigs of hemlock, spruce, and fir trees. This prevents tree growth and causes needles to drop prematurely have been literally sucking the life and sap out of the region's hemlocks.

Why do these trees matter?

These hemlock trees are particularly interesting to scientists and were first studied in the 1970s. They are some of the best examples of drought-sensitive trees in the U.S. Northeast. Prior to the 1970s, tree-ring studies were common only in the U.S. Southwest, where the science of using tree rings to describe past climate began. The old-growth hemlock trees in the Humpty Dumpty talus slope site proved that trees in the U.S. Northeast could capture drought information in their rings as well. They became the catalyst for developing more drought sensitive tree-ring studies across the region.

What will I learn?

The setting of this virtual lab is the Mohonk Preserve of Upstate New York, where you will learn some history of the area and how the tree-ring research here began. After exploring the Humpty Dumpty talus slope site using Google Maps, you'll gather data and evaluate the tree-ring core samples and analyze your data to determine the nature of paleoclimatea climate prevalent at a particular time in the geological past in the Northeast.

You will learn about how scientists work in the field and collaborate to search for clues to determine what past climate was like in this region. You will see how tree cores are produced using an increment borer and you will evaluate the ring patterns in a series of cores collected on the site.

To complete the lab, you will use an online tool called "Climate Explorer" to look at recorded drought data from the Mohonk Preserve region, and map it. Then you will compare the wet and drought years that you found in the tree-ring record in Part 2 to recorded meteorological data you found in Part 3 to see for yourself how well the trees capture drought events.

Learning Objectives

After completing this lab, you should be able to:

  • describe the nature of dendrochronology and why it is important.
  • explain why it is important to understand the ecological conditions of a site.
  • observe and record ring patters in digital samples and compare tree-ring growth to climate records.
  • describe how the analysis of tree-ring data can be used to describe changes in past climatic conditions.

References and Additional Resources

For more information about the science in this lab, consult the following papers and articles.