Pacific Gas and Electric Co. is failing to identify and trim thousands of trees near power lines that could pose dangers in wildfire areas and has deficiencies in record keeping and inspector training, a court-appointed monitor said in a report made public Wednesday by a federal judge.

The monitor said inspection teams, which included trained arborists, examined vegetation management projects already reviewed by PG&E’s contractors and found “at least one dubious tree” in nearly half the projects. Three trees, cleared by PG&E, were in contact with power lines, or a foot or less away, and “could have resulted in fatalities, injuries or serious damage” if not removed, the report said.

Based on inspections of more than 1,550 vegetation management projects, the monitor said, the company’s contractors are “missing numerous trees that should have been identified and worked under applicable regulations” and PG&E’s own program.

“Thus, not only is PG&E falling short of its (enhanced vegetation management goals) for the year, but the quality of the completed work is questionable,” the report said.

The report was filed publicly Wednesday by the monitor, Mark Filip, a former deputy U.S. attorney general, after U.S. District Judge William Alsup of San Francisco ordered it released. Alsup, who is overseeing PG&E’s probation from the 2010 San Bruno pipeline explosion, has told the company to respond to the monitor’s letter by Sept. 3 and he set a hearing on the matter for Sept. 17.

PG&E said it was working with the monitor to address the findings. The report said the monitor provided a “detailed, 65-slide presentation” to leaders of the utility’s vegetation and wildfire-safety programs on July 17 and is “building a good feedback loop with PG&E.”

Court orders and state law require PG&E to prune vegetation so that it is at least 12 feet away from its lines horizontally, maintain at least 4 feet of vertical clearance and remove 10 types of trees that have been involved in starting past fires.

In the first 53.5 miles of lines inspected, the monitor’s report said, PG&E appears to have missed 3,280 trees that should have been marked for trimming or removal.

PG&E said it provided training to its inspectors on April 1 after learning that they were not fully aware of the criteria for potentially risky trees. The monitor’s report said the training was “ineffective” and resulted in only a slight decline in the error rate.

The report also said the review of PG&E’s enhanced vegetation management unearthed “substantial record-keeping issues related to the Company’s pre-inspection and tree work processes.”

The company uses a software application called Arc Collector to track its assessments, the report said, but some employees are entering inaccurate locations or descriptions into the software, and others are not entering any data at all.

Workers are also supposed to mark trees for trimming or removal, but are not using the prescribed colors or symbols, the report said. And in projects that PG&E had designated as “complete,” the monitor’s team found 127 trees that needed further inspection or removal.

“Unless post-work verification is effective, uncorrected safety hazards and remedial errors and omissions will persist until at least 2020,” the report said.

PG&E has had serious record-keeping problems in the past. In one of its felony convictions for the San Bruno pipeline explosion, jurors found in 2016 that PG&E had known of two previous gas leaks but failed to enter them in its database — which contained “a ton of errors,” according to a company memo — or consider them in pipeline testing and inspection.

More recently, the California Public Utilities Commission has been reviewing its staff’s findings that the company repeatedly falsified certain safety-related internal records about its gas pipelines.

PG&E spokeswoman Lynsey Paulo said in an email Wednesday that the company shares the court’s focus on reducing fire risk and is working “transparently and cooperatively with the Federal Monitor and his team.”

“We appreciate their work evaluating compliance with our Wildfire Safety Plan’s Enhanced Vegetation Management program,” Paulo said in the email. “We understand and recognize the serious concerns raised by the monitor and we are taking immediate action to address these issues, which are consistent with our own internal reviews.”

She also noted that the company’s service area includes upward of 120 million trees that can grow onto or fall on its above-ground electric lines.

“While we have made progress in many areas to further enhance wildfire safety including vegetation management work, we acknowledge that we have more work to do,” Paulo said. “We are open to a range of solutions that will help make the energy system safer for the customers we serve.”

Bob Egelko and J.D. Morris are San Francisco Chronicle staff writers. Email: begelko@sfchronicle.com, jd.morris@sfchronicle.com Twitter: @BobEgelko @thejdmorris