Densification push likely to further shrink region's tree canopy, report says

An area nine times the size of Stanley Park has been covered in pavement and other impervious materials across Metro Vancouver's urban core since 2014, according to a report that notes the push to densify could come at a cost to the region's green spaces and tree canopy.

While the amount of land covered by pavement and buildings increased by four per cent in Metro Vancouver's urban containment boundary between 2014 and 2020, the tree canopy decreased by one per cent.

Increased growth, plus new provincial housing legislation that allows greater intensification of urban lots will likely lead to further tree canopy losses — and the increase of impervious surfaces, says the Metro Vancouver report, which will be presented to the regional planning committee on Friday.

The report cites the need for progressive tree retention and urban forest expansion strategy to offset losses, while Metro Vancouver faces an uphill battle to increase its canopy as more trees are being cut down than planted.

Tree planting must occur on an area about five times the size of Stanley Park to replace those that are expected to be lost to development, with an additional 80 square kilometres — an area about 20 times the size of Stanley Park — planted to achieve the regional district's goal of having 40 per cent of urban areas shaded by trees by 2050. Achieving that target will be challenging, the report notes.

Trees provide a range of benefits, including shading and cooling, carbon storage, stormwater management and homes for wildlife. A significant proportion of the nearly 600 people who died during the 2021 heat wave lived in neighbourhoods with limited or low tree canopy.

Impervious surfaces, on the other hand, are associated with higher temperatures, increased flood risk and poor water quality.

Metro Vancouver is hoping to increase the tree canopy to 40 per cent — an attainable goal despite the “considerable gap” between the current 31 per cent canopy cover level, according to the report.

The report also shows which areas of Metro Vancouver's urban core are closest to becoming a concrete jungle.

The urban areas of 11 communities, including New Westminster, Richmond, Tsawwassen First Nation, City of North Vancouver, Port Coquitlam, Delta, Vancouver, Anmore, White Rock, Langley City, and Pitt Meadows, exceed the 54 per cent regional average level of impervious surfaces.

The urban areas with the highest levels were in Richmond and New Westminster, where about 75 per cent of the land in 2020 was covered with hard surfaces that don't allow water to pass through, followed by Tsawwassen First Nation with 71 per cent. Those communities, along with Pitt Meadows, also saw the biggest increase in the amount of impervious surfaces added since 2014.

Lions Bay, Anmore and West Vancouver saw decreases to impervious surfaces in their urban areas during that time.

Surrey, Vancouver, Richmond and Burnaby had the largest areas of impervious surfaces compared to the region as a whole, with pavement and buildings covering about 120 square kilometres of Surrey's urban core in 2020.

The report noted 54 per cent of Metro Vancouver's urban containment boundary was covered in impervious surfaces in 2020, compared with 22 per cent of the region as a whole.

At the same time, tree canopy covered 31 per cent of lands in the urban core.