The upper part of the monument has an unusual and hard to photograph inscription that wraps almost all the way around it. It says "OUR SOLDIER BROTHER". It also gives the birth and death dates for Charles, 1835-1894.
Behind this tree shaped monument are individual tombstones for Charles and his parents. They look older, so the 1901 date on the severed branch must indicate when this family monument was put up. Perhaps by Charles' literal brothers? Or by his fellow soldiers? Because Mr. Barnes was indeed a soldier.
Confusingly there appear to be two men of this name who served in Wisconsin regiments during the Civil War. This one enlisted on February 4th 1862. After serving two years with the 17th Wisconsin is noted to have been in Company G of the 14th Wisconsin for most of 1864, mustering out at the end of that year. He may have been from New Buffalo Michigan.
The 17th Wisconsin regiment fought in most of the hardest battles in the Western theater. The men of the regiment finished their term of service in January of 1864, returning home for either civilian life or a "veteran's furlough". Barnes chose to re-enlist in a different regiment for some reason.