CHICAGO (WBBM) — A 2-1/2 year audit, timed to coincide with Arbor Day, found that the City of Chicago may have lost nearly $500,000 by failing to track which of its newly-planted trees were ailing, and seeking replacements.

As WBBM Newsradio 780’s Bob Roberts reports, the tree-planting program has been one of Mayor Richard M. Daley’s pet projects. In all, the city planted approximately 14,675 trees during the period audited, although the audit found the numbers impossible to reconcile with planting firms’ invoices.

LISTEN: Newsradio 780’s Bob Roberts reports

The contracts with each of its three tree suppliers specify that the city is to get free replacements, should the trees die or begin to fail within two years.

City Inspector General Joseph Ferguson said his audit found only 107 trees were replaced for free.

When WBBM 780 asked Ferguson if it is possible that hundreds of trees were purchased as replacements, he said, “It is, but the city paid for these trees. They paid for the planting of lots of trees. They paid for a guarantee to have failing trees replaced and they couldn’t track what trees they had in the field and what trees were actually replaced.”

Ferguson said the tracking system the Dept. of Streets and Sanitation’s Bureau of Forestry used to determine the dates when and locations where trees were planted was incompatible with the software used for customer service requests to 311.

The audit found 685 more trees planted than the number recorded by suppliers.

That troubled Ferguson, who wrote in the audit that the guarantees must be tracked “in order to ensure the agreements are properly enforced and to avoid waste of funds by paying for trees that should have fallen under the guarantee.”

Ferguson said the audit prompted the Bureau of Forestry to resolve the compatibility issues, and said the number of trees replaced in recent months under the guarantees reflects the 5 percent death rate his office projected.

Ferguson calls the 5 percent figure “conservative,” and said studies elsewhere of urban tree planting show failure rates as high as 50 percent. At 5 percent, Ferguson said the potential loss to taxpayers was $481,641.

The audit found that there has been little tracking done as city budget cuts have taken their toll on the Bureau of Forestry and the department as a whole. Ferguson recommends that Bureau of Forestry workers resume a physical review of recently-planted trees during the course of trimming and wants supplier invoices reconciled monthly.