A tree disease will require Yorktown to cut down one of its official Christmas trees.

An arborist diagnosed the town's Christmas tree at the John C. Hart Memorial Library with spruce canker, a common disease of spruce trees that are stressed by drought, winter injury or other factors.

The disease, known by its scientific name as cytospora canker, can badly deform trees by killing random branches throughout the tree. The town planted the tree last October.

According to the Cornell Plant Disease Diagnostic Clinic, cytospora is a fungus. It is less likely to invade healthy plants than weakened or wounded plants. Winter injury, improper pruning cuts or stubs, insect injury, mechanical injury, or previous disease increase the chance of infection by cytospora.