Want to contribute to a citizen science program looking at how trees interact with pollutants in different types of environments?


Students from across Canada are invited to be part of the Trans-Canadian Research and Environmental Education (TREE) Project. TREE is a citizen science program done in partnership between the CLS and the Mistik Askîwin Dendrochronology Laboratory (MAD Lab). Students collect and submit trembling aspen tree cores, soil samples, and a detailed timeline of environmental events in the area. Sampling kits are lent out and we cover the costs of shipping.

High School, Middle Years, or Adult Basic Ed.

Flexible Timeframes

Land-Based, Distance Learning

Data is collected from these samples across the country and is added to our citizen science database, where anyone can access, compare, and investigate further! This program is well-suited for classes in environmental sciences, chemistry, biology, land-based education, math, and more. Check out our Teaching Resources section for more info.

NSERC (logo in image) supports Student Programs and shipping of kits with the CLS Education Team.The Canadian Light Source is proud to offer the TREE Program and we acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) PromoScience to make this possible.

How It Works

The TREE Overview Guide summarizes the program, including the curricular and learning outcomes and the Indigenous Languages and Traditional Knowledge used in TREE. Listed below is a general outline of activities for participating in TREE. The Education Team is available to clarify and assist with any aspect of the program, just get in touch. 

  • Learning material and data is available for teacher or student access as needed for your schedule
  • Teacher completes the registration form to access a sample collection kit
  • CLS Education Team member contacts teacher and a TREE kit is booked
  • Class is sent a kit with tools for sample collection
  • Students research events in the sampling area and create a detailed timeline of all events that might impact tree growth (i.e. natural/environmental, industry, human, and climate events)
  • Students collect samples from trembling aspen and nearby soil from sampling area 
  • Samples, sample form, and the timeline (electronic version preferred but printed version acceptable) are sent to the CLS and the MAD Lab for data analysis
  • Data is shared with students and teacher once processing is complete - this timeframe is unpredictable - a report is provided as it becomes available
  • Data from samples is shared with the citizen science database
  • Students analyze and can compare their results with other classes across Canada


All this information, including the registration form and downloadable resources, can be found on our TREE website.

TREE Website


The TREE Program is a full partnership between CLS Education and the Mistik Askîwin Dendrochronology Laboratory (MAD Lab; logo in image).The CLS is excited to be working in partnership with the Mistik Askîwin Dendrochronology Laboratory (MAD Lab) in delivering the TREE program. The MAD Lab was launched in the spring of 2014 after moving to Saskatoon from Mount Allison University. The MAD Lab was formed to investigate tree ring related research questions in many areas of Canada and now through the tree ring chronologies they have created, the MAD Lab is able to understand the climate history of various location, date historical artifacts, and investigate how environmental contamination from humans has changed over time. Visit MAD Lab's website to learn more.

With the TREE program, MAD Lab is investigating the adaptability of trembling aspen (Populus termuloides) to toxins in environments across Canada. Trembling aspen are quite abundant throughout Canada, although not all of Canada, and they tolerate, even thrive, with much higher levels of toxins in their soil than other species of trees. They can potentially be used to remediate contaminated sites. In order to study this, a large and varied sample size of this species is required and this is where students from across Canada can help!

Teaching Resources

Dr. Colin Laroque, director of MAD Lab, teaching students about tree rings.The curricular foundation of the TREE program reflects current science education research, takes on an inter-disciplinary approach, is responsive to changing demographics across the nation, connects to Indigenous Ways of Knowing, and continues to be built upon. With respect to the diversity in learning throughout Canada, the TREE program attempts to ask broad questions that can be adapted to fit curricular outcomes in each province and territory.

Students will be learning about the life and nutrient cycles of trees, connecting to their communities, applying that knowledge to decipher their data from the tree rings, and learning how soil plays a role. These concepts are shared through downloadable modules (with print versions included in the kit), instructional videos, and adaptable lesson plans. These resources are made publicly available to make TREE easily adaptable to connect with curriculum across many subjects in Grades 6-12. Check out the links below on the TREE website for more info. 


Participation in this program requires that you commit to helping your students discover the environmental history of your community (constructing a timeline), collecting and sending to us at least 2 trembling aspen tree cores with associated soil samples according to instructions and the timeline you have created, and then sending the kit, samples, and timeline back to us. Kits are booked for approximately 1 week at a time for sampling.

Registration is open all year but there may be certain times that are better for collecting (winter does pose some challenges). Also, be aware that synchrotron data can only be collected when there is beam available and this will impact processing of samples. We process samples sent to us as quickly as we are able to, but cannot guarantee a specific timeframe. Contact us if you have questions and/or keep an eye on the TREE calendar or operations schedule (looking for green, normal day shifts) for when data can be collected.