Urban trees are important components of the landscape and offer numerous benefits; both socioeconomical and biophysical. Urban trees act as a sink for CO2 , helping to offset carbon emissions from
urban areas by removing the greenhouse gas from the atmosphere through photosynthesis. Environment
Canada develops estimates of Canada’s greenhouse gas emissions and removals which are submitted
annually to the United Nations as part of ongoing commitments under the United Nations Framework
Convention for Climate Change. As part of these reporting commitments countries are required to develop
estimates of emissions and removals of Greenhouse Gas that are the result of direct impact of human
activities in the Land-Use, Land-Use Change and Forestry Sector. Here, we present an approach which
involves sampling high resolution aerial photographs to determine urban tree coverage across Canada’s
major urban areas. Our results suggest Canadian urban areas have an estimated tree canopy cover of 27%.
This tree cover is estimated to store approximately 34,000 kt C and annually sequester approximately
2500 kt of CO2 . These estimates show significant improvement over previous methods used to provide
Canadian estimates. The methods developed here are easily repeatable which allow for temporal changes
to be analyzed and assessed over time