Two agile climbers scrambled up lofty trees to show opposition to council plans for a dual-carriageway in Priory Crescent.
Shaun Qureshi, 30, and 19-year-old Paul Mansfield braved a frosty morning at the start of their eight-hour vigil.
THey and other campaigners for the group, Parklife, fear the road widening scheme will destroy more than 100 mature trees and a large shrubbery area.
Mr Qureshi said: "We wanted to make a surprise protest in the trees to again bring the issue home to Southend people and others coming into the town.
"We were overlooking the Cuckoo Corner roundabout near Priory Park, so we had a good view of traffic and the public. It was chilly up amid the branches, but we were happy to do it.
"The police were interested in our demo and were content to let us carry on because it was peaceful.
"What better way of putting our message across than going up a couple of the threatened trees."
He and the group were determined to make a show because the Southend Council is likely to give the controversial new road scheme the go-ahead at a cabinet meeting tomorrow.
Parklife claims 25,000 residents have already backed its protest in the form of petitions and letters to newspapers.
Mr Qureshi added: "The council says that their views (the residents) should be taken with caution and that the park is not being touched.
"Therefore, we are left with no choice but to take up the occupancy in the first of the threatened trees as a peaceful but visible show of opposition on behalf of the people of the town."
Roger Weaver, Southend's executive councillor for transport, said: "Southend Council respects all protests as long as they are conducted in a legal and proper manner and the protesters don't put themselves or anyone else at risk.
"I would prefer people to use the democratic process when voicing their concerns but these protesters have made it clear they do not wish to follow that.
"The cabinet will be looking at all the responses it has received from protesters and hopefully come to a decision it can recommend to the full council.
"We have tried to work with the protesters' concerns and we are now not looking to take any of the park's land.
"However the protesters seem to have changed their aims and are now saying they do not want any trees to be cut down.
"The council has tried to accommodate their views."