Trees Can Help Save the World - Chapter 2
Watch complete playlist (Chapters 1-7) • Climate Change: How Tr...
For more information about the Canadian Agricultural Greenhouse Gases Program, visit: agr.gc.ca
To contact researchers:
agordon@uoguelph.ca
nthevath@uoguelph.ca
Edited Transcript:
In the previous chapter of this video series we introduced you to an exciting research study that’s being conducted in Canada. Researchers are scientifically quantifying how trees can reduce greenhouse gas emissions in farm fields.
Funded by Canada’s Agricultural Greenhouse Gases Program, the research project focuses on tree-based intercropping systems in Ontario and Quebec. Intercropping involves planting trees in rows and planting farm crops in the alleys between the rows of trees.
Here at the University of Guelph intercropping site, a hybrid poplar tree has been cut down and a well-defined area around the stump is being excavated. A host of researchers and students are collecting samples for their research projects. Amy Wotherspoon is a graduate student at the University of Guelph.
Wotherspoon: My role for this project is to quantify above and below ground carbon pools and fluxes for this 25 year old tree-based intercropping system. I’m here with teams from the University of Toronto, and graduate students and undergraduate research assistants from the University of Guelph to excavate above and below ground biomass for this hybrid poplar species.
The biomass samples will be taken to a university lab for analysis. The goal is to determine which tree species has the most potential for sequestering carbon. By storing carbon, trees remove carbon dioxide from the atmosphere.
The backhoe digs deep to unearth soil around the tree trunk. This enables the researchers to take samples from specific depths.
Wotherspoon: And we do that at different depths so that we can see how the carbon accumulates in the soil over time. The idea is that you have higher carbon concentrations closer to the surface because that’s where litter falls first, and as it decomposes we wanted to see how that carbon is distributed over time and what depth and distance from the tree.
Grid lines are drawn around the tree trunk to map out where the excavation will take place.
Wotherspoon: And we do that at four distances from the tree, so at 0.5, 1, 1.5 and 2 metres distance from the tree trunk to take soil samples.
As well as hybrid poplar, the researchers are focusing on red oak, black walnut, Norway spruce and white cedar.
Wotherspoon: We take three trees of each species so that we have a larger sample size.
A research team from the University of Toronto came equipped with a ground-penetrating radar device that can measure biomass underground. Researchers will compare readings from the device with the excavation results. If the results compare well, cutting down a tree to measure carbon biomass may no longer be necessary.
Wotherspoon: Now that our destructive sampling is all finished, we can head in to the lab to weigh all of our biomass samples, our roots and above-ground. We can also determine moisture content and carbon concentrations of our soil samples.
The research has come up with some interesting findings. For example, of the fast-growing tree species they studied, hybrid poplar can sequester more carbon in the least amount of time. But hybrid poplar trees have a short life-span.
Wotherspoon: So where they may only have a life span of 25 to 30 years, future research can be done in terms of implementing cutting cycles so that they can be planted over and over again to reach maximum carbon sequestration potential.
With the slow-growing tree species, white cedar has the most potential for long-term carbon sequestration because they live much longer and can be planted closer together.
The research study revealed that with all factors considered, one particular tree species has the most potential for carbon sequestration.
Wotherspoon: And we found that hybrid poplar was the highest in terms of net carbon because it can sequester the most in terms of above and below ground biomass, it produces a lot of litter fall which then contributes to long term soil organic carbon concentration.
Hybrid poplar is followed by red oak, black walnut, Norway spruce, and white cedar.
This research project is the first of its kind in Canada. The results clearly show how tree-based intercropping can benefit both farmers and the environment.
Wotherspoon: This is one of the largest research stations that we have, and since it’s been around for 25 years it’s showing great results and it really leads into where we can go next, and how we really need to help landowners adopt these kinds of systems to mitigate climate change and to have sustainable agricultural practices.
18 сен 2024
