RAPID CITY, S.D. (AP) - The top 40 feet of South Dakota's largest tree is dead and officials are not sure what happened.

The 300-year-old Ponderosa pine that towers 130 feet as the largest tree in South Dakota is known at Custer State Park as the "Big Tree."

The massive tree is the biggest but not the tallest in the state. It has survived fires and beetle attacks over the years.

State forestry specialist John Ball tells the Rapid City Journal that he plans to climb the tree this fall to try to find out what happened.

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