The cherry trees on Heathfield Road, Frecheville, were among 19 which had been planted in tribute to members of the community who were killed in the Second World War.
Their removal today sparked concern among some local residents, who claimed they had not been notified about the work.
But Sheffield Council said both trees within the small memorial garden were diseased and their felling had been approved by the Royal British Legion.
It also said three new beech trees would be planted within the next fortnight, increasing the number of trees in the memorial garden - where some trees had already been lost over the years - to 15.
An existing bench is also due to be replaced with a new commemorative wooden one 'in due course'.
The council last year approved the felling of 41 war memorial trees across the city, having claimed it would cost Â£500,000 to save them - a figure which was hotly contested by tree campaigners, some of whom argued it had been deliberately 'inflated'.
At the time, officers said works had already been carried out in 2014 to replace two trees for 'condition reasons' and there had been a request from veterans to replace the remaining war memorial trees as they were 'poor specimens'.
"The proposal is to discuss with local residents and the Veterans Association a plan to renew the memorial trees on Heathfield Road. Any tree replacement work required by the contract has already taken place," the report stated.
It is just over three years since a new plaque was unveiled on the road, explaining how the trees had been planted to honour local servicemen who made the ultimate sacrifice.
Today's felling appeared to have come as a shock to some local residents, despite the council saying it had consulted thoroughly about its plans.
RAF veteran Colin Hierde said: "I helped to put the memorial plaque up and I was disgusted to see they're taking down trees planted in memory of dead servicemen, without any notice."
Fern Emerson said: "I'm shocked by what they've done. When I was young, I remember everyone gathering to lay wreaths on these trees."
Councillor Bryan Lodge, cabinet member for environment and street scene, said the council had 'worked closely' in recent months with local residents and members of the Royal British Legion to discuss its plans to 'improve and rededicate' the memorial site. He claimed they had supported the proposals.
"As part of our dialogue, we also asked for people's views on plans to replace more of the trees and encouraged suggestions to greatly improve the immediate area in its entirety, to ensure a fitting tribute could remain for years to come," he added.
"We had an overwhelmingly positive response and as a result we have decided to not only replace two of the trees but also plant an additional tree and replace the existing old bench with a new wooden one to commemorate that 2018 is the 100th anniversary year of the end of the First World War. This work will go ahead in coming weeks."
The council said all the work is being carried out as part of its Â£2.2bn Streets Ahead contract with Amey.
The Star has attempted to contact Frecheville Royal British Legion.