The tree had apparently been hit by a lightning strike sometime in the overnight hours and was "burning deeply" when firefighters arrived.
Photos posted by the department to Facebook showed the glowing embers on the trunk of the tree.
Glowing embers can be seen on a tree that apparently had been struck by lighting in Millbury, Mass. on Sunday. (Millbury Fire Department)
The fire department said an ash pit could be seen at the base inside the tree, which showed how hot it was.
"There was a steady breeze blowing right into the opening of the tree, basically fanning the fire," the fire department said.
The glowing inside of a tree after it was apparently struck by lighting in Millbury, Mass. early Sunday. (Millbury Fire Department)
The National Weather Service's Boston Office said Saturday night on Twitter that scattered showers and thunderstorms were moving across southeast New England at the time, with isolated storms expected across the state after midnight.
Lighting typically strikes tall objects such as trees and skyscrapers because their tops are closer to the base of the storm cloud, according to The National Severe Storms Laboratory.
Firefighters douse a smoldering tree after a lightning strike on Sunday. (Millbury Fire Department)
"However, this does not always mean tall objects will be struck. It all depends on where the charges accumulate," according to the agency. "Lightning can strike the ground in an open field even if the tree line is close by."
When a tree is hit, water inside the tree trunk is turned into steam as energy from lightning heats the air anywhere from 18,000 degrees Fahrenheit to up to 60,000 degrees Fahrenheit, according to the NSSL.
"If it gets under the bark into the surface moisture of the wood, the rapidly expanding steam can blast pieces of bark from the tree, and the wood along the path is often killed," the agency states.