Far more trees may be in danger of being cut down along Dublin's proposed ''Bus Connects'' 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.
Professor Mills said: "The public have seen differing news reports of the estimated loss of trees along the routes, sometimes varying between 500 and 1,000 trees.
"The National Transport Authority 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 National Transport Authority has stated it does not yet know how many trees will need to be felled.
Professor Mills told the Sunday Independent he has 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. 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 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 that do a valuable job cleaning the air of those gases.
The professor said he does not claim to know the number, the sizes or the ages of the trees destined to be cut down but he called for more specific information to be made available by the National Transport Authority.
Neither has there been a cost-benefit analysis of the effects of felling the trees, he said.
"A colleague of mine did a simple thing of putting the routes on a satellite photograph of the city and simply clicking where all the trees are.
"I'm not saying they are going to cut all these trees. I think they have a responsibility to show where they are going to take away the trees," he said.
He said the value of trees along busy roads are not given due consideration. They act as a buffer to traffic noise and pollution. They boost health and well-being, provide valuable screening, shelter, privacy, and bio-diversity and enhance the character and attractiveness of streets.
Currently, London is planting one million extra trees at a time when Dublin stands to lose possibly thousands of trees to road widening, he said.
Grainne Mackin, spokesperson for the National Transport Authority, said the felling of trees along the Bus Connect routes will be minimised as much as possible.
The numbers of trees to be removed will not be known until further examination of the alignments of the routes is complete, she told this newspaper.
"I fully understand the emotional attachment people have to trees and their urban space. Residents are telling us they would prefer to have a one-way system on their street to restrict car access if they can keep their trees. We are going to work on our designs during the summer.
"Then we will go back for a second round of public consultation in the autumn. Our design team includes urban realm architects and landscape designers.
"We will minimise the impact on trees. We will put a re-planting programme in place as close as possible to the original locations. Trees live and trees die and there is a life cycle.
"We are looking at one-way systems for cars, more restrictions on parking and removal of parking, and traffic restrictions. People won't move out of their cars unless we get reliable bus lanes," she said.
"Dublin City Council Parks and Landscapes division have 60,000 trees in the city plus 40,000 trees in city parks while we may be impacting on 1,600 trees," she said.