Members of the National Tree Collections of Scotland, led jointly by the Forestry Commission Scotland and the Royal Botanic Garden Edinburgh (RBGE), will share expertise and resources.
Launching the scheme at Scone Palace, Scotland's environment and climate change minister Stewart Stevenson said:
"Many of the species in the National Tree Collections are under threat in their own natural environments. These sites will both safeguard against this threat of extinction and also help maintain the value of collections."
The five initial sites, all publicly accessible, include three of RBGE's four gardens:
- Royal Botanic Garden Edinburgh.
- Benmore Botanic Garden, Argyll.
- Dawyck Botanic Garden, Scottish Borders.
- Kilmun Arboretum, part of Argyll Forest Park.
- The privately owned Scone Palace Pinetum, Perthshire.