The trees are part of a stand of poplars that were planted in the late 1920s along the Avon River, between Madras and Manchester Sts.
“All the trees were comprehensively assessed, including a second independent assessment," said Christchurch City Council head of parks Andrew Rutledge.
"Two trees were identified as having some decay at their base.
"Further testing showed that the decay is not yet extensive, however, it is expected to worsen.
“Failure of these trees when decay is present is hard to predict so we have decided to proactively remove the trees, given their proximity to a popular gathering area alongside the Margaret Mahy Playground."
“We are also looking to replace about five cherry trees along Harper Ave that have been identified as having health or structural problems.
“The cherry trees along Harper Ave are an iconic symbol of Christchurch in the spring but some of them are getting quite old.
"We’re putting in place a staged replacement plan for the older trees so that as they come to the end of their natural life, there are new ones to replace them.
"That way we can ensure our much-loved avenue of cherry trees is protected for future generations.’’
This year 15 new cherry trees will be planted along Harper Ave to replace the five trees being removed.