Charleston, S.C. ? As cannons thudded around Charleston Harbor this week in commemoration of the start of the war that extinguished slavery, the audiences for the 150th-anniversary events were nearly all white. Even black scholars lecturing about black Union troops and the roots of slavery gazed out mostly on white faces.

The reasons blacks stayed away are not exactly a mystery: Across Dixie, Civil War commemorations have tended to celebrate the Confederacy and the battlefield exploits of those who fought for the slaveholding South.

But the National Park Service is trying to make anniversary events over the next four years more hospitable to black people.

“We’re trying to broaden the story to go beyond the battlefields to the home front and to talk about 150 years later, if much of the reason for the war was freedom for enslaved people, how far have we come?” said Carol Shively, a spokeswoman for the Park Service sesquicentennial in the Southeast.

The anniversary of the April 12, 1861, bombardment of Fort Sumter that plunged the nation into its bloodiest war was marked in Charleston on Tuesday by hundreds of people. Only a few blacks attended a pre-dawn concert of period music or were on hand for a ceremony re-creating the first shot a few hours later. One of the black people present was a Union re-enactor who threw a wreath into the water and then saluted.

“I think it’s very painful and raw” for blacks to attend such activities, said the Rev. Joseph Darby of Charleston, who is black and was not there for the Fort Sumter commemoration. “If you’re going to be authentic in the way you re-create it, it would be hard to filter out the triumphal air of the firing on Fort Sumter.”

On Wednesday, the Park Service sponsored events about blacks outside its Fort Sumter tour boat dock. It included lectures on slavery and on the Union 54th Massachusetts, the black unit depicted in the 1989 movie “Glory” starring Matthew Broderick, Denzel Washington and Morgan Freeman. But out of about 50 people attending the lectures, there was only one black, a woman who declined to be interviewed.

Dot Scott, president of the local chapter of the National Association for the Advancement of Colored People, said even such programs may not be enough to get blacks involved in 150th-anniversary events.

“It’s almost like celebrating with the enemy,” she said. “I personally began to have a feeling of why would I want to be a part of it?”

The national NAACP has said the activities should neither romanticize the South nor ignore that slavery was the principal cause of the war. Both Scott and Darby credit the National Park Service with working hard to make events inclusive.

Darby, the minister, said one sure way to interest more blacks in the commemorations would be to remove the Confederate banner that has flown on the Statehouse grounds in Columbia since the Civil War centennial.

“There would be a lot of black folks who would come out if our Legislature would in 2015 officially decide the war was over and take the flag down,” he said.