The government is to plant 250,000 ash trees to help beat the fungal disease ash dieback.
By planting the new trees they hope to find ones that are resistant to the disease.
It's hoped by studying these resistant trees, it may be possible to manage the effects of ash dieback on the UK's ash trees.
According to official figures, outbreaks of ash dieback have been found on 427 sites across the UK.
The new trees will be planted in the east and south east of England where most of the ash dieback outbreaks have happened.
It's hoped that by exposing the trees to the disease in these areas, it will become clear which of them can fight it off and which can't.