Toronto's 10 million trees are worth an estimated $7-billion or about $700 per tree and the benefits of maintaining an urban forest outweigh the costs, says a new report.

"The replacement value (what it would cost to remove a tree and replant a similar one) of the 10 million trees that make up Toronto's urban forest is valued at over $7 billion," TD Economics chief economist Craig Alexander said in an analysis published Monday.

The city's urban forest provides residents with over $80-million -- about $8 per tree -- in environmental and cost savings every year, the report found.

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"For the average single family household, this works out to $125 of savings per annum."

Every dollar spent on annual maintenance of the tree stock returns between $1.35 and $3.20 worth of benefits and cost savings per year, according to the report's estimates.

The average annual maintenance cost of a tree in Toronto is about $4.20. For every dollar spent on maintenance, trees return up to $3.20 to the community, but this can vary based on type of land the trees are located on, the study says.

Trees also help to boost land property values, support higher rents and generate greater property tax revenue, said the study.

The dollar values cited in the report "only quantify a portion of the overall value provided by urban forests. Many of the benefits that are important to communities -- aesthetic values, recreational spaces, community importance -- are difficult to quantify and are not included in our valuation."

Mr. Alexander said in an interview that the study did not factor in estimates of the economic impact of last year's ice storm on the city's trees.

Among the annual benefits provided by the more than 116 tree species:

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$53.95-million from the reduced strain on water transportation and infrastructure thanks to rain and wet-weather flow interception

$19.09-million from air pollutants absorbed, removed and avoided by street trees

$6.42-million from energy saved through shading and climate moderation

$1.24-million from carbon sequestration and emissions avoided through energy savings

The amount of particulate matter removed annually by Toronto's urban forest is equivalent to the amount released by over one million cars or 100,000 single family homes, the report calculates.

"Efforts to maintain our urban forests make a world of difference, and the vast majority of Toronto's urban forest is in good or excellent condition" despite such invasive threats as the European Gypsy Moth and the Emerald Ash Borer.

"The cost savings produced by our urban forests make it clear that keeping the green on our streets, keeps the green in our wallets."