A public inquiry into £15m housing plans opposite the historic home of Sir Walter Scott has been told their visual impact would be "negligible".
Mr Chard said trees should provide adequate screening
Landscape expert Matthew Chard carried out the assessment on behalf of developers M & J Ballantyne.
He concluded that a belt of trees at Netherbarns would provide adequate screening for the 79-house development.
Opponents have rejected that claim saying it would be a "blemish" on a property which is a national treasure.
Mr Chard told the inquiry he had carried out his study under guidelines set out by the Landscape Institute and the Institute of Environment Assessment.
"I would acknowledge that this is a category-A listed building within a designed landscape," he said.
"But the fact remains that the principal views from the listed building would not be adversely affected by the Netherbarns development."
Mr Chard added that even in winter when the leaves had fallen off trees there would only be a "negligible effect".
His findings came under attack from objectors to the housing development near Galashiels who have described Abbotsford and its surrounding landscapes as a "national treasure".
Protesters said the plans would be a 'blemish' on the house
Andrew Douglas-Home, a trustee of the house, used the analogy of the Mona Lisa portrait when he questioned Mr Chard.
"If you put a very small pimple on the face of the Mona Lisa then what are you going to see - are you going to see the pimple or the Mona Lisa?" he asked.
"Your eye will be drawn to the one blemish."
Mr Douglas-Home said Sir Walter Scott built Abbotsford in an unspoilt landscape.
"If you suggested to him a building site directly opposite was going to enhance that landscape it stretches credulity," he added.
Scottish Borders Council approved the application from M & J Ballantyne last May on the casting vote of the chairman of the building and development control committee.
The application was called in by the Scottish Executive after objections from Historic Scotland.
Opposition has also been lodged by the National Trust for Scotland, Scottish Natural Heritage and the Save Scott's Countryside campaign group.
The inquiry is being heard in front of reporter Michael Thomson who will prepare a report for Scottish ministers to make the final decision.
It is expected to last three days with a site visit planned early next week.