You are hereGlyndwr’s Oak
According to the National Gazetteer of Great Britain & Ireland 1868, Newcastle is described as ‘a hamlet…..where are the remains of an ancient castle and an oak said to have been planted by Owain Glyndwr.’ It is said the locals considered the oak to be possessed by evil spirits who harmed anyone that damaged the tree in any way. So it was left to grow old and decay until one night when the oak was extremely old its last branches were felled in a storm. The locals gathered up the wood and took it home to burn on their fires. It is said cottages of those villages mysteriously set on fire after the wood had been taken inside.
Newcastle is not named on the map below, so I cannot be sure how accurate it can be.