What is this tree

What is this tree

Observation - What is this tree. Description: The reddish brown bark of this tree is causing me problems. It is growing in a large mixed wood that was once the 'garden' of a hunting lodge so may have been planted.

The reddish brown bark of this tree is causing me problems. It is growing in a large mixed wood that was once the 'garden' of a hunting lodge so may have been planted.