Pine Grave Marker Treatment Using SP-11 2017-04-25T02:59:21+00:00

Pine Grave Marker Treatment

By Nathan Henry, NC Office of State Archaeology

I treated 5 grave markers total that varied from well preserved above ground to highly degraded below ground. Just 2 were still intact below ground. They came from Greenwood Cemetery in New Bern, NC, a historic African-American cemetery developed in the mid-19th century. It was a burying place for free-blacks just prior to the Civil War. The earliest interment I could find record of was 1856, although I think the majority of the graves were from the 20th century. My guess is that these markers were intended to be temporary until a stone marker could be afforded.

Markers in the ground at Greenwood Cemetery in New Bern, NC.

Markers in the ground at Greenwood Cemetery in New Bern, NC.

All the markers look to be longleaf pine. The 2 that were still standing were obviously from the center of the tree, which explains the longevity in the soupy southern climate. Unfortunately any names that may have been painted on the markers have been lost to the ravages of time.

Grave markers fresh from the ground.  Below ground, they were nearly completely waterlogged.

Grave markers fresh from the ground. Below ground, they were nearly completely waterlogged.

I typically treat the wood with boric acid before treatment, but in this case I had to treat the markers for termites (which discolored the lichens). The markers were removed during the winter of 2013 and when brought into the lab, the termites became very active. After destroying the termites, the markers were soaked in Borax and then SP-11 was brushed on until they were saturated. The penetration was excellent throughout. They were then covered with plastic to slow dry. A small amount of mold formed on the surface and was treated topically with no further issues.

The main reason I used the SP-11 in this case was that I was pretty sure the storage/display conditions would be less than perfect (high humidity). To me that is THE HUGE advantage over PEG.

The grave markers were badly degraded by insect and microbial decomposition and look the same post-treatment as when they were recovered (a good thing), except for some discoloration of the lichens that were still attached.

Grave markers after treatment with SP-11 and completely dehydrated.

Grave markers after treatment with SP-11 and completely dehydrated.

They have been drying in the lab for approximately a year and half and they seem to be dimensionally stable with no color change.


Nathan Henry is an Assistant State Archaeologist and Conservator at the Underwater Archaeology Branch of the NC Office of State Archaeology.