Birmingham is at risk of losing its reputation as a city where residential streets are lined by mature trees.

A national one-day conference held to celebrate the importance of trees in towns warned a legacy from Victorian times is in danger of disappearing.

The event, at Millennium Point, involved more than 100 delegates from across the country who urged local authorities to do far more to protect existing trees and to encourage new planting.

Professor Chris Baines, a leading environmentalist, said trees enabled people to lead healthier lives by filtering polluted air, provided shade, and created an attractive setting for recreation.

They also increased property values and improved urban character.

Prof Baines said urban trees were under threat from a variety of sources. Insurance companies increasingly recommend the felling of trees near to houses to minimise claims for structural damage, while pavements dug up to lay utility cables could result in damage to roots.

Prof Baines added: "Many trees in public spaces and alongside roads are reaching maturity as they were planted in Victorian times and they now need a significant investment of skill and money if they are to remain safe and healthy.

"We need to take our legacy of mature trees much more seriously to give us time to plan for the next generation of the urban forest."

David Ritchie, chairman of the National Urban Forestry Unit, said: "We need to find more effective ways of championing trees in towns."

Birmingham City Council is to launch an investigation into the value of trees in the public highway. A scrutiny committee will draw up new guidance on tree husbandry.

Committee chairman Ray Hassall said: "Trees are our natural air conditioners and, with more and more of our children suffering from asthma and other health problems, we need our street trees more than ever."

There were warnings earlier in the year that the planned privatisation of the council's highways unit could lead to a cull of roadside trees.

Critics of the plan claimed private companies would attempt to save money on maintenance costs by getting rid of thousands of trees.