An operation has begun to remove protesters who have been trying to halt work on the new £40m bypass in Dalkeith, Midlothian.
A protester is removed from one of the trees
Sheriff's officers were assisted by a specialist team from Wales in removing four protesters on Monday.
Save Dalkeith Park members claim the road, which will link the A720 and the A68, will cut through the park and destroy the natural environment.
Officials said the road is designed to ease traffic congestion in Dalkeith.
Three people who had taken up position in trees were arrested and a fourth who was in a tunnel was removed later in the day.
Transport Scotland said the operation to remove the protesters in Langside began at 0900 GMT.
Warrants were served on the protesters and a specialist body called the National Eviction Team - which has dealt with similar protests in other parts of the UK - arrived on site.
When the warrants were served, one of the protesters left the site voluntarily.
A spokeswoman for Transport Scotland said: "Just before 9am the operation to move protesters from the site of Langside, which is outside the country park, began.
"The operation so far seems to be going well, obviously it does need to be done as safely as possible.
"There are four sites in total to clear and we expect it will take about two weeks to clear the sites."
She added: "We've had regular meetings with the protesters over the past few months and obviously they have refused to leave.
"We have sought and gained warrants to remove them and it is the start of that process today."
Five oak trees at the Langside site need to be cut down to make way for the bypass.
The spokeswoman said: "The reason this is being done now is environmental, it is outwith the bird-breeding season so it is the best time to take them down."
Protesters fear the road will destroy a large part of Dalkeith Park - an area of more than 1,000 acres of farmland and woodland just outside Edinburgh.
Protesters claim the bypass will destroy the environment
They argue it is a haven for wildlife enthusiasts, cyclists, anglers, horse-riders, walkers and others and that it is visited by as many as 50,000 people every year.
Protesters fear the bypass will cut the park in two and endanger the wildlife there.
Scottish Socialist Party leader and Lothians MSP Colin Fox said the protesters wanted the route of the bypass to be reassessed.
He added: "The protesters in Dalkeith Country Park are not revolutionaries but their basic demands for a reassessment of the situation have fallen on deaf ears and so they are forced into a situation in which non-violent direct action is necessary to make their voices heard."
Mark Ballard, Green MSP for the Lothians, said the new bypass was a "prime example of the Scottish Executive's poor planning and reckless use of public money".
The cost of the operation has been estimated at £100,000 a day.