He told Amateur Gardening: "I was appalled to see an avenue of trees had a chainsaw put through them. We donate trees to schools. This is not a criticism of the RHS: it has good recycling policies. But it may now have to quiz exhibitors on what will happen to every element of a garden after a show.
The silver birch trees were felled by Frosts Landscapes after the show.
Dodd, who designed the Hampton Court One Show garden, posted pictures of the felled trees, which were from Hillier and were worth £1,000 each, on Twitter.
Frosts managing director Ken White said: "A large number of trees and shrubs were donated to charities. But half a dozen large trees were cut down because they would not have survived, due to stress. They would not have coped with being transported again. They are being used to make insect and beetle mounds. They have been recycled."
Garden designer David Domoney said the tree house will be installed at Chestnut Tree House Children's Hospice and that 500 plants were given to Thrive.
The RHS said it does not condone felling of healthy trees but that the landscaper had decided they were not viable.