The group wants tougher measures to stop trees being cut down
Campaigners have called for better protection for trees after claiming 9,000 were lost in London last year.
A third of those trees were large, mature and in streets, according to the charity Trees for Cities.
Despite recent pledges from Mayor Boris Johnson to plant 10,000 new trees in the city's most deprived areas, the group said this would not be enough.
Old trees should be given the same level of protection as historic buildings, the organisation claimed.
"We'd like to see much protection of bigger trees, especially the big mature trees," said chief executive Graham Simmonds.
"I think what we should be doing is thinking about historic trees as we do about historic buildings," he added.
"We value architecture and we should value trees in the same way. We wouldn't just knock down a building that has historical significance, and we should do the same with trees."
About 320 mature woodlands across south-east England are also under threat owing to the development of airports, roads and buildings, according to the Woodlands Trust
The charity wants tougher legislation to stop the cutting down of woods in the area.