A dozen trees at Royal Mail's depot in Hampstead are earmarked for a chop or to be felled entirely.
The trees, including Sycamore, Birch and Ash, surround the Hampstead Delivery Office in Shepherd Walk.
On its application, Royal Mail says none of the trees are diseased and there are no fears they may break or fall.
It says there is no issue of damage to the property through subsidence, or damage to drains and drives.
However, a Royal Mail spokesperson said following an inspection and risk assessment of the trees in December, its contractors advised of the works required.
They added: "Royal Mail is committed to protecting the natural environment across all of our sites, including the protection of trees wherever possible.
"Of the 16 trees identified in our planning application, 12 are scheduled to be pruned or have branches removed.
"This work has been recommended on grounds of safety and to provide more light.
"The remaining four trees are due to be felled. One of which poses a danger of collapse, the other poses a risk to the building and the remaining two are dead.
"We will only consider the removal of trees once all other options have been exhausted.”