Phytophthora ramorum – known as Sudden Oak Death – is a fungal disease and has been found on two larch trees on the upper western side of the park.
It poses no risks to human health.
FERA (The Food & Environment Research Agency) has been informed and under its instructions the Council will now remove the affected trees, along with 12 other larch trees to reduce the risk of the disease spreading.
This work will take place on Tuesday, October 9 with the felling of the trees and removal of timber estimated to take around two days. Signs will be put up keep park users informed.
Phytophthora spores spread through water, including airborne droplets which can be carried on animals, and through infected water in soil.
The trees will be removed, taken away and destroyed in accordance under the requirements of the notice issued by FERA.
Councillor Ashley Govier, Cabinet member for Environment, said: "Outbreaks like this are beyond the Council’s control and we are acting quickly, under instruction from FERA, to contain and eliminate this problem.
"It is important that we destroy all the infected trees to prevent this problem spreading and the measures we are taking are vital to ensure that this is done properly."
Councillor Huw Thomas, Cabinet member for Sport, Leisure and Culture – including parks, said: “We have highly trained council staff in place to identify these types of occurrences and are taking rapid action to tackle this problem. There will be a small amount of disruption to the park, which the Council will keep to a minimum. This is a wonderful green space and we will be working hard to help ensure there are no further outbreaks.”