Studies show that when schools add trees, test scores go up.Alex Slitz/The Associated Press
Peter Kuitenbrouwer is a journalist, a Registered Professional Forester and the author of a forthcoming book about maple syrup.
The other day, in the midst of a heat wave that suffocated central Canada, this newspaper brought us the story of a five-year-old at a public school in Ottawa, sent to hospital for heat exhaustion. The accompanying photo shows the child and his mother seated on a picnic table in the schoolyard, surrounded by grass and pavement – and one tree.
As a forester, I volunteer with a program of Forests Canada called Forestry in the Classroom, whose goal is to connect ”the next generation of forest stewards with forestry and environmental professionals.” This spring I visited a school in north Toronto to take a class of Grade 5 students to a nearby forested ravine, to help them identify trees and to evaluate tree health. On my arrival at the school, I was shocked to find the playground a barren wasteland. Despite the spacious suburban setting, instead of trees the school offered plenty of parking, an asphalt schoolyard surrounded by chain-link fence, a patch of grass and, against one side, a half-dozen trees. The kids ran squealing happily in the yard at recess, kicking and bouncing soccer balls and basketballs, but it was April. I wondered how hot the yard would be in June.
Now we know. When the heat comes, students across the country cook like buns in the ovens of their classrooms – and fry in playgrounds. The Ottawa story quotes Karen Littlewood, president of the Ontario Secondary School Teachers’ Federation: “People are sweltering in the classrooms with the inability to do anything to actually address it, other than go outside and sit under a tree.”
Alexandra Mullins with her son Emmitt, who was sent to hospital for heat exhaustion while at his elementary school in Ottawa last month.Dave Chan/The Globe and Mail
But isn’t that exactly where the teachers should take their students? In fact, there is a basic and very Canadian solution to the heat risks our nation’s schoolchildren face from climate change: plant more trees in schoolyards across Canada. Give our students shade.
The Toronto District School Board, the country’s largest board, with more than a quarter-million students at close to 600 schools, proposed to do just that. In a 2013 Urban Forest Management Plan, the board warned that, by 2040, temperature rise will require air conditioning six months of the year, compared with just one month when the report came out. One solution: plant trees. The TDSB website now says in the past 18 years it has planted 4,000 “large native shade trees” at over 300 schools. Hmm. Half the board’s schools each have a dozen new trees. In Canada, one of the world’s great forest nations, that seems a pittance.
The grade schools I attended in Quebec did not need such tree cover: school got out before it got too hot. That is no longer the case. Sure, we can use electricity to cool our schools, at great expense – or we can opt for trees planted on the south and west sides of schools, to shade them from the hot sun.
Trees, which are green, living infrastructure, do so much more: they suck up ground water and transpire it as tiny droplets, cooling the air; they soak up rain, reducing the need for sewer upgrades; studies even show that when schools add trees, test scores go up. Dr. Janani Sivarajah at the University of Toronto and her fellow researchers compared tree canopy cover to test scores for students in Grades 3 and 6 at hundreds of Toronto schools and found that, even after accounting for the effects of income and mother tongue, students at schools with more trees achieved higher grades. She notes that “human exposure to green space … can restore attention-demanding cognitive performance.”
Ask a doctor: What are the signs of heat illness?
What is it like in a heat wave, in a classroom with no air conditioning and no trees around the school? I can tell you. On the last week of school I traveled for another Forestry in the Classroom presentation to a crowded grade school on the northern frontier of Toronto. The students (36 Grade Sixes!) sat packed and roasting in their furnace of a second-floor classroom. A lone, sealed window housed a broken air conditioner. I felt bad for the teacher. I did not have to ask the students twice to follow me outside. A park abuts the schoolyard; we had to walk a few minutes to get to the trees, which beckoned from the far end. The school-board report recommended planting more trees closer to schools; that has not happened here.
Foresters measure tree diameter at breast height (1.3 metres from the ground). Wrap the tree with a tape measure to learn its circumference. Then divide by pi. Turns out pi is a bit advanced for Grade 6, but these kids were quick learners. How tall was the tree? We had a student stand at the trunk. Once we knew the student’s height, we could estimate tree height. “How many Omars tall is this tree?” I asked. Everyone’s favourite part, as we evaluated a silver maple, a Siberian elm and a black walnut tree, was standing under each tree in its shade. The shade of a tree is a good place to learn.