Using a pet cemetery as a control study to optimise clandestine burial search in the Nordic region with insights into seasonal variation in vegetation, topography and temperature

The unique climatic conditions of the Nordic region, particularly the freeze-thaw cycle, present both challenges and opportunities for detecting clandestine burials. By understanding seasonal environmental and vegetational indicators, forensic archaeologists can develop more effective methods for locating burial sites to aid in forensic investigations, archaeological surveys, and humanitarian projects. This pilot study investigates the detection of clandestine burials in a Nordic environment, focusing on a case study of a 50-year-old pet cemetery in Finland. While domestic pets are a poor substitute to human bodies, their burials are very similar to clandestine human burials. The burials are usually small and shallow, and the bodies are often bare or wrapped in cloth or plastic. Pet cemeteries are also often less regulated, in remote locations, and have less visitors, allowing for discreet research. The study site was monitored for changes in ground temperature, vegetation and topography during the thawing period 2021-2024. The aim of the study was to determine whether burials show seasonal variation that would make them easier to detect during a specific season. Ground surface temperature surveys revealed significant differences between burials and undisturbed ground during early spring. Vegetation analysis identified early blooming flowers and specific persistent plants growing over graves as potential indicators of past burials. Topographical changes, including mounds and depressions, were more pronounced during the thawing cycle, aiding in the identification of burials. These findings are valuable, for instance, for detecting clandestine and forgotten graves in historical contexts, such as old cemeteries, mental hospitals, prisons and childrens' homes.