Note: This work is under development but has been released temporarily for classroom testing purposes. Look for the full series of TREX (Tree Ring Expeditions) labs in the fall of 2017.

Before we get started...

Download the Student Activity Sheet: Launching an Expedition worksheet/Word (Microsoft Word 52kB May9 17)

How do scientists launch an expedition?

In following series of labs, you will take virtual expeditions to collect data and analyze tree-ring cores to search for clues about the past climate in a number of interesting localities, from a scorching deserts to a lush river valley. You will travel along with a group of tree-ring scientists (dendrochronologists) to explore their research sites. You will conduct hands-on lab activities, watch videos, analyze the actual data from the each expedition, use Google Earth to explore these places, use online interactives, and discuss your results with your instructor and classmates. Let's think about what it takes to launch such an expedition. How would you go about it? Where would you start?

Becoming a scientist: inspiration and serendipity

Every research effort begins in the mind of a scientist who has an interest and a question, or a series of questions, that they are passionately driven to answer. How are these questions generated? What inspires scientists to entertain science research as a career and drives them to travel across the globe to find the answers to these questions? And what role does serendipity have in influencing their career paths? To help answer these questions, listen to two scientists describe their journey to becoming a scientists.

First listen to Dr. Ed Cook talk about what it means to him to be a scientist.


Now here how Dr. D'Arrigo feels about her journey to becoming a scientist.


Next watch Dr. Cook discuss his work in the Hudson Valley and describe what drew him to the area to engage in research in the Humpty Dumpty talus slope region.


Now watch Dr. Arrigo describe how she began a long-term research effort in Mongolia.


Stop and Think

1. What drew Dr. Cook to the Humpty Dumpty talus slope area?

2. Why are moisture-stressed trees ideal for studying past climate change?

3. What are the best parts of being a scientist as described by Dr. Cook and D'Arrigo?

4. What are some of the challenging aspects of being a scientist? as described by Dr. Cook and D'Arrigo?

5. What role did serendipity play in each scientist's career?

6. What drives Dr. D'Arrigo as a scientist?

7. What advice do Drs. D'Arrigo and Cook have for students who are thinking about a career in science?

What do dendrochronolgists do?

Would you like to hike, camp, and be in the great outdoors? Would you like to explore exotic locations all over the world? Are you interested in how life and environment on Earth have evolved over time and how knowing what happened in the past can help us make decisions about the future of life on our planet? Well, maybe a career in dendrochronology might be a good career choice for you. To answer questions about the nature of climate on Earth during the past 2,000 years, tree rings offer a good proxy record of how environmental conditions have changed on Earth.

Finding and then exploring a prospective site is always a first important step to determine whether it is suitable for answering the research questions that interest you. This involves traveling to sites located in rugged terrain or with harsh climates. Look at the tree-ring research sites below by clicking on the buttons below. Zoom in and look at the sites carefully. What difficulties do you think you might encounter if you were to spend a week at these sites gathering data?

Bristlecone Pine

Mendenhall Glacier

Once you have collected core samples from a number of trees at the site, they need to be preserved and brought into a laboratory for analysis.

Tree-ring patterns are studied with an array of different instruments. Look at a panorama of a working tree-ring laboratory. Zoom in so you can see the details of what lies on the table, and decorates the walls.

Tree-Ring Laboratory

Tree-Ring Laboratory Core Room

Finding the right kind of trees to study

Doing tree science is not as simple as it might first appear. The climate record over long periods of time is not preserved in the vast majority of trees you see in forests. As a dendrochronologist, you need to search for special trees, certain species that are in areas where their growth is slow, so slow that many years will be recorded while they grow. One such tree is a bristlecone pine which grows in Utah, Nevada and eastern California. They are long-lived and very resistant to harsh weather and bad soils. The oldest known specimen is named Methuselah and is a whopping 4,765 years old!

What characteristics do dendrochronologists look for when seeking trees that will give them the best chance to reconstruct past climatic conditions? Watch the video below and answer the Stop and Think questions.


Funding your expedition

Once you have a site selected and have lined up collaborators to help you in the research effort, how will you acquire the funds to pay for the travel, living expenses, salaries for your team members, and all the rest? The expeditions represented by the series of TREX labs are based on major field campaigns, most of which were funded by The National Science Foundation (NSF). To apply for a grant to do your research, it is required that you submit your ideas in response to a request for proposals, or RFP. In 15 pages of text, you must make your case: Why is your research an important step forward? How does it build on previous work in the field? How will the results of your study be of value to the larger scientific community? How will your research findings be disseminated? How much will it cost to do the work? Are your goals reasonable? Are you qualified to do what you are proposing to do and do you have a strong team assembled to work with you?

Once you submit your proposal, you must wait up to 6 months to see if your proposal has been selected for funding by a jury of your peers. Keep in mind that perhaps hundreds of other professional scientists are vying for a limited amount of money slated for the particular proposal category. Often as not, you will be rejected and have to go back to the drawing board. Scientists need to learn with rejection and be tenacious, adaptable, and willing to keep refining their ideas and keep turning in proposals to fund their work. It's a huge part of being a successful scientist.

It doesn't mean that you need tons of money to do science, take a look at what these students have done (AMNH Young Naturalist Awards), but keep in mind when you are reading a scientific paper, or hearing about a new study in the news, that there was a whole process that happened first.

Another way to be involved in science research is to become a citizen scientist. Many of the processes that scientists want study occur on a massive scale, with mountains of data, making them difficult to study using ordinary research methods. In many cases, there is just too much data for a single scientist, or even a group of scientists to process. So, having a large number of research participants makes it possible to increase the amount of data that can be collected and analyzed. It also enables you to participate in, and gain a greater understanding of the scientific process. Check out the projects at Zoouniverse. Look at the diversity of projects at the site. Select one you might be interested in participating in.

Want more information about doing tree-ring research?

If you would like to try your hand at tree ring research, you can get started by purchasing a few simple tools. You will learn how these tools are used in the TREX lab sequence. A tree coring apparatus (about $240) can be purchased at Forestry Suppliers. Visit The Ultimate Tree-Ring Webpages for tips, advice on cleaning kits for your core apparatus, and more information. A wealth of additional information can be found at the NOAA Tree Ring site.


Stop and Think

1. What types of trees are the most useful for dendrochronologists to use in their research?

2. Why aren't trees grown in landscaped areas useful to study in tree-ring science?

3. Why are some parts of the tree ring light colored and some dark colored?

4. Temperature is the limiting factor for growth of what kinds of trees?

5. What types of instruments did you see in your tour of the Tree Ring Lab?

6. What kinds of tree core samples did you see in the Tree-Ring Core Room?

7. Which of the citizen science projects are you most interested in participating?