A creek winds through a partially wooded landscape northwest of Toronto. Located on the edge of Ontario's Greenbelt, this area lies in an ecological region that would be optimal for reforestation to help mitigate climate change.Nick Iwanyshyn/The Globe and Mail
In the 19th century, the forests that surrounded some of Canada’s oldest and most populated cities were key to the economics of European settlement and helped lay the foundation for a new country.
Now, those same places could become essential to Canada’s future – not through further clearing and development, but by encouraging the trees to grow back.
That’s the takeaway from a comprehensive analysis that seeks to optimize the country’s 2 Billion Trees effort.
The federal program was launched in 2021 to help Canada meet its climate objectives by planting two billion trees over a 10-year period for carbon storage. So far the program is not on track to meet that goal, having been hampered at the outset by the pandemic and inadequate planning, as documented in a 2023 report from Canada’s Auditor-General.
But Ottawa has pressed ahead. Last November, officials said that 157 million trees had been planted while announcing funding for another 160 million.
The new study, published Tuesday in the research journal One Earth, could help make the program more effective and data driven.
Conducted by the conservation group Nature United in collaboration with federal scientists and other partners, it is the most systematic attempt yet to identify the optimal locations for restoring forest cover in a way that meets the program’s climate objectives.
“It’s asking where in Canada are we going to achieve the highest growth rate of trees at the least cost,” said Ronnie Drever, senior conservation scientist with Nature United who led the study.
The analysis also considers how to address other program goals beyond climate mitigation, such as benefiting species at risk and improving access to nature-based recreation.
The findings show that the best return on investment will come from spreading efforts to parts of the country where those many goals can be met in different ways. Overall, the optimal results are not to be found in the remote boreal wilderness but in diverse pockets of land that are relatively close to the cities and towns that most Canadians call home.
“If we want to get the most from this restoration effort, it’s this portfolio approach that’s going to deliver that,” Dr. Drever said.
In particular, the study finds that the best value comes from restoring mixed and deciduous forest to parts of rural Ontario and Quebec and similarly appropriate forest types to the Maritime provinces and to southern British Columbia – all places where tree cover has gradually been eliminated through two centuries of human activity.
Dr. Drever and his colleagues left out built areas and high-quality agricultural land. They also excluded vast swaths where dense forest cover is not natural, such as the Prairies and across the wetlands and tundra of the Far North. Finally, areas that are currently tree-covered or where industry is typically obligated to replace trees after logging takes place were not included since planting there would not amount to adding new forest to Canada’s current inventory. This left an “area of opportunity” for forest restoration totalling roughly 19.1 million hectares (191,000 square kilometres) spread across areas with widely different ecological characteristics.
Where to add two billion trees
An analysis of available landscapes for restoring tree cover across Canada reveals that some areas are more favourable than others for achieving a range of conservation goals. In total, about 1.2 million hectares are needed to plant 2 billion trees. In each of the following scenarios, the best places to add trees depends on the goal.
= Optimal locations for forest restoration
based on specific goal
(Combined Area = 1.2 million hectares)
Distribution of optimal locations
(Hectares per ecological region)
0
1
50
1,500
10,000
50,000
Scenario one: Highest rate of tree
growth for lowest cost
Excluded regions are not naturally tree covered or are unsuitable for
restoration.
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario two: Most accessible high growth
locations for forest restoration
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario three: High growth locations that meet the largest number of different goals including: lowest cost, greatest accessibility, greatest benefit to species at risk, best for connectivity between natural areas, best for providing freshwater, best for nature-based recreation
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
THE GLOBE AND MAIL, SOURCE:
RONNIE DREVER, NATURE UNITED
Where to add two billion trees
An analysis of available landscapes for restoring tree cover across Canada reveals that some areas are more favourable than others for achieving a range of conservation goals. In total, about 1.2 million hectares are needed to plant 2 billion trees. In each of the following scenarios, the best places to add trees depends on the goal.
= Optimal locations for forest restoration
based on specific goal
(Combined Area = 1.2 million hectares)
Distribution of optimal locations
(Hectares per ecological region)
0
1
50
1,500
10,000
50,000
Scenario one: Highest rate of tree growth for lowest cost
Excluded regions are not naturally tree covered or are unsuitable for restoration.
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario two: Most accessible high growth locations
for forest restoration
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario three: High growth locations that meet the largest number of different goals including: lowest cost, greatest accessibility, greatest benefit to species at risk, best for connectivity between natural areas, best for providing freshwater, best for nature-based recreation
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
THE GLOBE AND MAIL, SOURCE:
RONNIE DREVER, NATURE UNITED
Where to add two billion trees
An analysis of available landscapes for restoring tree cover across Canada reveals that some areas are more favourable than others for achieving a range of conservation goals. In total, about 1.2 million hectares are needed to plant 2 billion trees. In each of the following scenarios, the best places to add trees depends on the goal.
= Optimal locations for forest restoration based on specific goal
(Combined Area = 1.2 million hectares)
Distribution of optimal locations
(Hectares per ecological region)
0
1
50
1,500
10,000
50,000
Scenario one: Highest rate of tree growth for lowest cost
Excluded regions are not naturally tree covered or are unsuitable for restoration.
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario two: Most accessible high growth locations
for forest restoration
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
Scenario three: High growth locations that meet the largest number of different goals including: lowest cost, greatest accessibility, greatest benefit to species at risk, best for connectivity between natural areas, best for providing freshwater, best for nature-based recreation
Yukon
NWT
Nunavut
B.C.
N.L.
Alta.
Sask.
Que.
Man.
PEI
Ont.
N.S.
N.B.
THE GLOBE AND MAIL, SOURCE: RONNIE DREVER, NATURE UNITED
The researchers estimated that it would require about 1.2 million hectares to grow two billion trees at the typical density of a Canadian forest.
To determine which of the available hectares would best suit the program, the study considered growth rates as well as cost and accessibility. This favoured areas in south-central Canada, much of Atlantic Canada and the Pacific coast. The authors narrowed the list down further by considering which locations could achieve additional goals based on species richness, improving the connectivity of the natural landscape and serving freshwater and recreational needs.
While no single region best satisfies all goals, those that were rated most highly were often in transitional areas between the most developed and most natural parts of Canada. Such places are often privately owned.
The results could help policy makers tailor incentives to encourage tree planting in areas that are likely to produce the most long-term benefits.
“Planting the right trees in the right place” definitely matters for achieving a successful outcome, said Zach Xu, an economist with Natural Resources Canada who contributed to the analysis.
He cautioned that the results should not be taken as a road map to specific tree planting sites at a local scale but rather as an indicator of which parts of the country should be the focus for the 2 Billion Tree program, depending on which goals are prioritized.
Megan de Graaf is a New Brunswick-based program director with Community Forests International, a not-for-profit organization that receives funding from the 2 Billion Tree initiative.
She said the study confirms what she and her colleagues learned about the province even before the federal program was under way: There is room to significantly boost forest cover using a mix of native species that are long lasting and climate resilient.
“This region has the potential to sequester and store a lot of carbon,” she said. “If you plant a tree here, all things being equal, it should grow well and should stick around for a while.”
Ms. de Graaf said the study should offer useful guidance for the federal program, which has laboured to hit its stride in the face of a complex task.
”We want to see this program deliver on its promises, but in the best way possible so that you’re not just planting trees for the sake of planting trees,” she said. “You want trees that are actually going to be meaningful and beneficial. So that takes some work.”