More trees face being cut down along Dublin's proposed BusConnects routes than previously estimated, a university professor has warned.
More than 4,700 trees have been identified as growing within a 20m-wide corridor along the 16 bus routes earmarked for possible major road-widening, said Gerald Mills, Associate Professor of Geography at University College Dublin.
The installation of enhanced bus lanes and cycle lanes is proposed to ease traffic congestion and make public transport faster and more attractive to car users.
"The public have seen differing news reports of the estimated loss of trees along the routes, sometimes varying between 500 and 1,000 trees," said Prof Mills.
"The National Transport Authority (NTA) has still not given us any specifics on the trees to be cut down.
"It is reasonable to expect that the proposers have acquired information so that they can do a complete environmental-impact analysis of the consequences of tree removal."
The NTA has stated it does not yet know how many trees will need to be felled.
However, Prof Mills said he had compiled a report which counted the number of trees along each bus corridor by placing the proposed bus routes map over a satellite image of the city.
All trees within a 20m-wide zone along each road route were mapped and counted.
As well as that, all trees within a 10m zone were also counted.
His report identified 1,000 trees within the 10m zones, growing within five metres each side of the centreline.
It showed 4,734 trees within a 20m zone along the routes. These are trees that are growing within 10m on each side of the centre of the road.
He also calculated the amount of carbon dioxide greenhouse gases that these trees remove from the air along the routes.
He found that the trees growing within 10m either side of the centre-lines remove and store the equivalent of carbon produced by 8,973 cars using those routes twice a day.
The trees also absorb other pollutants from the air.
He said it was somewhat "ridiculous" to talk of the benefits of reducing greenhouse gases by easing traffic congestion through road widening while at the same time cutting down possibly thousands of mature trees.
He said they did a valuable job ridding the air of those gases.
The professor said he did not claim to know the number, the sizes or the ages of the trees destined to be cut down.
He called for more specific information to be made available by the NTA.