content is less than twenty percent, wood-decay fungi cannot grow. While fungi may be present at lower moisture contents, they are unable to continue deteriorating the wood without additional moisture. Moisture contents from twenty to thirty percent indicate areas of concern where moisture is sufficient for fungi to grow but not sufficient to indicate advanced decay. Moisture contents above thirty percent are often an indication of advanced decay with internal voids and/or surface deterioration. Recent precipitation or watering may affect the reading by artificially raising the moisture content, which can obscure the actual long-term conditions. Although wood species can affect the moisture reading displayed by commercially available moisture meters, the variation is typically not significant enough to require adjustment for cemetery artifacts. However, the presence of high levels of salt (absorbed from the soil or in marine environments) can greatly increase the reading displayed on moisture meters and an adjustment may be required to provide the actual moisture content.
Fig. 11. Taking moisture readings on a grave marker.
Annual Journal of the Association for Gravestone Studies