A revolutionary new technique to revitalise old trees is being tested at a forest in Dorset on Tuesday.
The ground around the aged trees will be blasted with nitrogen gas, to loosen the soil around the roots.
The soil has become compacted because of the number of people walking in Parkstone Park, Ashley Cross, which has restricted the trees' growth
The treatment should allow the trees' roots to grow normally. If it works it will be used elsewhere in Dorset.
The technique has already been used successfully at Kew gardens.
After the ground has been opened up with the gas, they will put organic fertilisers into the root area - along with special spores.