Yew trees have been long associated with churchyards. They are believed to be the longest living organisms in Europe, the oldest have been shown to be over 4,000 years old. Which begs the question which came first, the church or the tree?
It is known that the yew was sacred to native Britons so it is likely that the early Christians built their churches on existing sacred pagan sites. Sites which could have been established around yew trees. The yew is evergreen and its sap blood red, both observations which could easily be blended with the beliefs of eternal life and the death and resurrection of Christ.
On the other hand, yew trees could have been purposely planted since they are poisonous to animals which would discourage farmers from allowing their cattle to graze in the churchyard. It is well known that the wood of the yew was used for longbows but churchyard yews are likely to have been protected.