The trees which line this path are evergreen Yews (Taxus baccata). The Yew was planted in places of burial for centuries and there are many explanations for this: they have particularly strong and durable wood and were needed in medieval times for making longbows and arrows but they could not be planted in fields as they were poisonous to cattle.
And so they were planted in churchyards which would also keep passing drovers out. For early Christians the tree symbolised everlasting life and the patient wait for the Resurrection. Edward I decreed that yews should be planted to protect the entrance of churches, Being toxic they are considered trees of death.