Tree Canopy Study helps city understand green infrastructure

OTTAWA — A new study says the National Capital region is almost half covered with a tree canopy.

The wealth of green spaces is a defining element of Canada’s Capital Region, and a new study has measured the size of its extensive tree canopy – trees cover almost half (46 per cent) of Ottawa–Gatineau, including the National Capital Commission’s (NCC) assets. The NCC, City of Ottawa and Ville de Gatineau have jointly released the very first region-wide mapping analysis of the tree canopy in collaboration with the University of Vermont Spatial Analysis Laboratory.

The study, Tree Canopy Assessment: Canada’s Capital Region, was formally released yesterday (Sept. 25) as part of Tree Canada’s events to celebrate National Tree Day in Canada’s Capital Region.

Tree Canopy Assessment: Canada’s Capital Region measured the tree canopy, the layer of tree leaves, branches and stems that provide tree coverage of the ground when viewed from above. This study has established that the tree canopy covers 46 per cent of the land mass within the boundaries of the City of Ottawa, Ville de Gatineau and NCC properties.

“The tree canopy assessment done by the National Capital Commission, City of Ottawa and Ville de Gatineau shows the growing importance of urban forests to Canada,” Tree Canada’s Mike Rosen said. “With 83 per cent of Canadians now living in urban areas, knowing more about the canopy cover and the benefits of trees to our communities is essential for municipal planning. This report is an excellent example for Canadian municipalities and a first step in line with the recommendations of the Canadian Urban Forest Strategy.”

When integrated with other data, such as property land use or demographic variables, the information and the maps in Tree Canopy Assessment: Canada’s Capital Region provide vital information about where to encourage more tree growth which will help governments and their citizens chart a greener future.

“Thanks to our partners at the NCC and Ville de Gatineau, the results of this Tree Canopy study will provide us with a tool to help prioritize our tree planting efforts,” Mayor Jim Watson said. “The City of Ottawa’s commitment includes planting 500,000 trees over this Term of Council, and I look forward to continuing to collaborate as we work to improve our urban tree canopy and protect our region’s existing trees for the benefit of our communities.”

Highlights of the Tree Canopy Assessment

• Seventy-four percent of NCC lands are covered by tree canopy, a result that reflects the number of parks and protected areas under NCC’s management. Gatineau Park and the Greenbelt contribute more than 35,000 hectares of tree canopy.

• Ottawa’s urban area has 31 per cent of its land covered by tree canopy; this includes the inner urban area bounded by the Greenbelt, as well as the suburban areas beyond the Greenbelt.

• Gatineau’s urban area, which includes farms and green spaces, has 45 per cent of its land covered by tree canopy.

Quick facts

• The tree canopy assessment relies on remotely sensed data in the form of aerial imagery, and light detection and ranging (LiDAR). These datasets, which have been acquired by the NCC, City of Ottawa and Ville de Gatineau, are the foundational information for tree canopy mapping.

• The combination of sensor and mapping technology enabled the mapping of the Capital Region’s tree canopy in 1,000 times greater detail than ever before. From the street tree in an Ottawa suburb to an old-growth tree in the forests of Gatineau Park, every tree over two metres tall in the Capital Region was included in the assessment.

• Urban density, the number of parks, management practices and land use history are factors that contribute to define percentage of tree canopy cover in urban areas.

• The total cost of the study, Tree Canopy Assessment: Canada’s Capital Region is approximately $31,000, which was shared among the three partners.

• Tree canopy provides numerous ecosystem benefits to citizens: air and water pollution reduction, storm-water control, moderation of high summer temperatures, aesthetic views, wildlife habitat, and community sense of place. These benefits ensure not only the daily well-being of residents but also contribute to a region’s livability.

• Interactive maps are available to the public to navigate the data. These maps will provide a large harvest of data for future research and analysis.