Compulsory purchase orders are expected to be served next week by Wicklow County Council to clear the way for a major road-widening scheme on the N11, between Kilmacanogue and the southern end of the Glen of the Downs.
It has been estimated that more than 2,000 trees in the picturesque glen will be felled so that the existing road can be doubled in width to dual-carriageway standard to cater for the estimated 20,000 vehicles a day using the N11.
Mr Mick Foster, manager of programme planning and services at the National Roads Authority, conceded that a large number of trees would be lost, but he said that what were taken away would be "more than replaced" by new planting.
He pointed out that the £18.5 million road scheme, which has been under discussion for several years, had been the subject of an environmental impact statement as well as a public inquiry into the compulsory purchase order.
The Glen of the Downs had "featured very prominently" in the EIS because of its high amenity status and value in terms of wildlife. "The principal conclusion was that the route of road through the glen did least damage."
Mr Foster admitted that there would be "short-term disruption" to flora and fauna in the glen from the construction of a second carriageway east of the existing N11, but it would ultimately "enhance the character of the area."
He said that NRA projects involved felling "quite a number of trees", but their replacement "far outnumbers anything taken down". The Portlaoise bypass had reintroduced indigenous trees which had been "lost for generations."
Mr Foster said it had been open to anyone to object to the scheme for the Glen of the Downs. But the only objections related to a proposal to close Quill Road, to the west of the N11, and replace it with a new link road.
In response to these submissions, the then Minister for the Environment, Mr Brendan Howlin, deleted the Quill Road replacement scheme when he confirmed Wicklow County Council's compulsory purchase last January.
The Minister's order was appealed to the High Court by another group of local residents, who favoured the original proposal, on the grounds that the decision had been made without hearing any evidence, submissions or views from them.
Their action was finally settled last week, with the road scheme as modified by the Minister being amended further to improve some 400 metres of Quill Road, and this cleared the way for the CPO to become operable from tomorrow.
Mr Foster said the NRA expected that preliminary work would start before the end of this year. The scheme includes two interchanges, one in Kilmacanogue and the other in the Glen of the Downs, and two overbridges for local roads.
