The city's forestry department may be losing millions of dollars a year on botched contracts with private arborists, the city's auditor general has concluded.

Beverly Romeo-Beehler's investigation found almost two thirds of the work crews she studied either didn't go near the trees they were supposed to be servicing, or wound up at coffee shops, plazas, residential houses and on streets with no trees — all while supposedly working on the city's dime.

"This could mean that part of the eight hours of work the City paid for was not spent on City-related work activities," she wrote.

"The estimated potential loss in productivity is approximately $2.6 million per year."

The urban forestry department annually spends about $67 million maintaining the city's 10 million trees, she noted.

Romeo-Beehler compared the activity logs of 45 private work crews with the GPS readings on their vehicles. She said she found discrepancies in 28 of those crew records.

The city paid three private forestry companies about $1.7 million a month in 2018. The auditor general estimates wasted time by those crews costs the city about $2.6 million a year. (City of Toronto)

After deducting things like travelling time and questionable stops, it appears those crews were actually working on city duties for only about 2.8 hours a day, she found.

"These things make me very angry," Mayor John Tory said Tuesday.

"We've got to after the ones that didn't do the work they charged us for, to take legal proceedings to recover some of that money."

He also wants to look into prohibiting some of the private contractors listed in the auditor general's report from doing any further work for the city.

Beverly Romeo-Beehler, the city's auditor general, released a report this week that calls into question the efficiency of forestry crews. (CBC News)

As for why the city's Parks, Forestry and Recreation Division didn't catch the problems, Tory said any large corporation can have blind spots.

"There aren't too many big organizations out there that achieve perfection in terms of of being able to keep tabs on everything that's going on," he said. "That's why you have auditors."

Although most of the problems appear to be with private companies working under contract to the city, none of which were named, the city's own crews did not escape criticism.

This map, included in the auditor general's report, points out several 'questionable stops' in a forestry crew's schedule. (City of Toronto/Auditor General)

Romeo-Beehler said that because the city-owned trucks are not equipped with GPS units, she couldn't compare those crews' activity logs with their actual locations at any given time of day.

But of 139 log books she examined, from both city and contractor crews, 57 "have missing data, or contain entries that should have been questioned," she wrote.

A City of Toronto forestry crew working at a job site in Etobicoke Wednesday, April 30. The auditor general is recommending better oversight of both city and contract forestry crews. (Gary Asselstine/CBC)

She said those entries included, "time spent on dead trees ... locations with no trees...and maintenance (watering) on a tree stump."

At least part of the blame for the problems lies with city staff, Romeo-Beehler says in her report:

"We found that Urban Forestry did not meet the required minimum number of on-site and quality control inspections in both 2017 and 2018," she wrote.

"Forepersons only conducted 60 per cent of required on-site inspections."

To combat the problems, Romeo-Beehler makes a number of recommendations, which will be presented to the city's audit committee at its meeting Friday: