‘Special’ trees whet interest
When eight milimetres of rain fell on McArthur Island Park on June 23, a staggering 100 litres of water ran down the trunk of a single American beech.
That “one, crazy tree” is what Julie Taylor Schooling points to when explaining why she’s decided to spend two years studying the way 40 trees in the North Shore park intercept and funnel rainwater.
“That is not a tree you’d want in a sidewalk situation or anywhere where erosion is a concern or anywhere where you’ve got unstable soils,” said Schooling, a
masters student in the environmental-sciences program at Thompson Rivers University.
For the past few weeks, Schooling and a team of volunteers have been measuring stemflow — the amount of water that flows down a tree trunk when it rains — on 40 McArthur Island trees of varying species.
Each tree is fitted with a collar, which funnels the rain into a 17-litre bucket, placed inside a larger plastic tote.
In most cases, Schooling said, the bucket has enough room to catch any rain rolling down the tree.
But, in the case of the beech and a couple other high-flow species (certain types of maples and Schubert chokecherries), the extra room the tote provides has been essential.
During the heavy rain on June 23, Schooling said the beech’s tote “was just bulging out” when volunteers checked in on it.
Even a more recent three-milimetre rainfall saw the beech tree produce almost a full bucket of flow.
“We’re looking at this tree going, what makes you so special?” said Schooling.
“We’ve got some time to figure this out — is it bark, is it branches, is it leaves? It’s going to be interesting to try and tease that all apart.”
She’s hoping her research, conducted in partnership with City of Kamloops, will show what trees can ease groundwater problems, and which might make them worse.
“It’s a right-tree, right-place thing,” she said.
While other researchers have studied rain-tree interactions, Schooling said most of the work has focused on forests, not individual trees in urban settings.
“Compared to natural situations, people have much more control over what gets planted in an urban situation,” she said.
“This is just adding in another layer to that decision-making.”
To volunteer with the project, or learn more about Schooling’s work, go online to kamloops.ca/stormwatertrees.