Some open habitats restored from woods and forests tend to scrub over.
Heathlands and bogs are particularly prone to birch and pine colonisation. Removing the former tree cover leaves bare ground that is readily colonised by tree seedlings arising from seed already there or arriving on the wind from trees nearby. Scattered trees or small clumps may be acceptable on the restored open habitat but if the regeneration is too dense, it will grow to form woodland and the valued open habitat will once again be lost.
Methods are needed for preventing and controlling tree colonisation on open habitat restoration sites.
Blanket bog and lowland raised bog restoration experiments are being assessed to see how different restoration treatments affect the amount and density of tree colonisation of the restored bogs. These may show that some restoration methods are better than others in this respect.
Trials of a range of control treatments for dealing with dense tree seedling establishment on restored heathlands and bogs are planned. These will compare control strategies, including pulling seedlings by hand, using clearing saws, chainsaws and various herbicide application methods to cut or kill the new trees at various ages. Follow-up monitoring will be important to see whether the colonisation tendency reduces as ground vegetation recovers.
For further information about this work please contact Russell Anderson.