About Gail Langellotto

I'm a Professor in the Department of Horticulture at Oregon State University, where I also coordinate the statewide Master Gardener Program.
Dendrometer, around the trunk of a red maple tree.

From time to time, we will highlight citizen science projects which may be of interest to OSU Extension Master Gardeners. Please visit our ‘Get Involved‘ page, for guidance on using approved Citizen Science projects to help fulfill the Master Gardener service hour requirement in Oregon.

This post is modified from a recruitment email provided by Dr. Michael Just who oversees the citizen science project, ‘A Tree’s Life‘.

A Tree’s Life‘ is a citizen science project that tracks tree growth, as one indicator of climate change. This project is perhaps one of the easiest ways to participate in citizen science. The time commitment is extremely low (a few minutes per year!), and their target species (Acer rubrum, commonly known as red maple) is a ubiquitous tree in urban and suburban yards.

Trees provide a suite of ecosystem services that improve human and environmental health. However, urban trees are subject to environmental stressors, including increased temperatures and drought. These stresses may reduce ecosystem services and make tree more susceptible to arthropod pests. The objectives of ‘A Tree’s Life‘ are to understand how climate and urbanization affect tree pests, growth, and health, and ecological services like carbon sequestration, air filtration, and water filtration.

Despite the importance of mature trees, we do not know much about the effects of warming on tree growth and services. This is largely due to the difficulties in experimenting with mature trees; you cannot move trees to warm spots. It is not practical to warm trees with heaters. Without information on how trees respond to warming and urban stress, there is no basis for selecting tree species and planting sites that will allow trees to thrive with minimal management or intervention.

Urban areas are warmer and often have higher carbon dioxide concentrations than rural areas. Warming and urbanization can reduce tree growth due to water stress, pests, and other factors. On the other hand, warming might increase tree growth and health due to longer growing seasons. These contrasting urban tree responses allow us to use urban warming to predict changes beyond cities that might arise due to global change. Thus, cities may be sentinels that predict how plants and animals respond to climate change.

The goal of ‘A Tree’s Life’ is to monitor red maple growth in urban, suburban, and rural areas. This is where you come in! Volunteers are needed to monitor the growth of red maples in their own yards. The project will provide you with a dendrometer, which is a tool that measures tree trunk growth without injuring the tree. The dendrometers will need to remain on the tree for at least a year, hopefully longer. You would simply need to report the tree growth (and a few other details), about once a year.

Although your time commitment is small, your efforts will provide valuable data to determine how different altitudes, latitudes, and urban conditions affect tree pests, tree growth, and carbon sequestration.

Right now there are very few citizen scientists in the PNW. Thus, participation by Oregon’s gardeners would make a big difference!

If you are interested, please fill out our Participant Sign-up Form, or visit the A Tree’s Life website for more information.

For more information, please contact Michael Just.

This post is part of the series How Science Works: A Guide for Gardeners.
Follow along to discover how science relates to your own garden. 


The core logic of science is that you can test ideas or answer questions, by systematically gathering evidence (or data), and then considering how that evidence supports or refutes your idea.

Of course, there are lots of intermediary steps in the process, including doing initial research into the question, so that we understand what is already known about the study system, the biological process, or the organism that is the focus of our question.  We then form a testable hypothesis, stating what think will happen.  Next comes the test of the hypothesis, through careful and controlled observation or experimentation.  Data is gathered and analyzed, specifically to see whether or not the outcome of your experiment either lends support or helps refute your hypothesis.  These steps in the scientific method are often portrayed as linear an uni-directional.

Sometimes, science is portrayed as a linear process.

In reality, the scientific process is an iterative, rather than a linear process.  The scientific process a continuous and ongoing cycle between theory and data.  Here, the word ‘theory’ is used to represent an explanation, or a logical framework, that represents our current understanding of the way that things work.  Theory is used to classify, interpret and predict the world around us.

In fact, it is much more accurate to portray science as a cyclical or iterative process, where questions are constantly re-examined and refined, in the context of new evidence or data.

For example, one common theory in ecology is that:  as the size of your yard or garden increases, so too will the number of species that inhabit your garden.  This is known as the ‘species area relationship’.

For quite some time, scientists believed that the number of species would increase, as a direct function of the size of habitat available to those species.

But, even after theories have been formed, scientists continue to ask question, gather additional data, and consider how what they knew . . . Or thought they knew . . . Aligns with any new information or data they may gather.  Good scientists must know and consider previous observations, and synthesize this existing data with new observations . . . All in an effort to refine and improve theory.

If we go back to our species area relationship, you’ll notice that the graph is linear.  For a long time, this is how scientists thought biodiversity worked: as habitat size increased, the number of species in that habitat increased.  But, after gathering more data, scientists realized that the relationship is more of a curvi-linear relationship.

Increasing the size of a habitat, or having a larger garden, increases the number of species you will find . . . But only up to a point.  At some point, you’re going to hit the limits of the species pool in your vicinity, such that increasing garden size results in fewer and fewer new species in your garden.  The number of species eventually levels off, rather than continues to increase.

We now know, due to systematic observation and experimentation, that the number of species does increase as habitat size increases, but only up to a point. Eventually, the number of new species in an area will level off, even as the size of habitat increases.

This is one of the most beautiful things about science ~ it allows for, and even encourages repeated and critical analysis of ideas.  Critical analysis is especially common for new ideas . . . But even established ideas ~ explanations that have long gained acceptance ~ are subject to critical analysis, review and revision, as new data becomes available.

Want to learn more?

Check out UC Berkeley’s fantastic ‘Understanding Science‘ site. A recommended reading for this post is the ‘How Science Works‘ publication, pages 1-3.

How does this apply to your garden?

Consider how the process of inquiry is, in your own garden. Have you ever made an observation that brought many questions to mind? Perhaps you saw a caterpillar that you could not identify, and you wanted to know more: what is the species?; is it new to this area?; what are its host plants? Once you found the answers to your original questions, did it bring more questions to mind? Congratulations! You’re thinking like a scientist!

If you’ve ever had this type of circular experience of inquiry ~ where an observation led to questions, and the answers to these questions led to more questions ~ consider sharing your experience in the comments.