Conservation process of water-damaged herbarium specimens at the Harvard University Herbaria

Abstract

Abstract In December 2009, following an upgrade of the Harvard University Herbaria's heating and cooling system, a pipe burst in one room, resulting in the soaking of specimens in the adjacent cases. The soaked specimens were removed, and the degree of water damage was assessed. The saturated specimens were placed in plastic bags and immediately transferred to a walk-in freezer set at -20°C. Slightly wet specimens were spread out to air dry. Restoration of the frozen specimens involved tests to determine the most effective method for restoring them to usable condition. Test specimens of no scientific value were intentionally soaked, then dried using two procedures: (1) silica gel desiccation and (2) vacuum freeze drying. Freeze-dried specimens did not adhere to each other as much as did those that were dried with silica gel and was the method chosen. Upon their return, the dried specimens were sorted into groups: (1) those that were immediately ready to be returned to the collection, (2) those requiring minor repair, such as reattaching detached labels or plant parts, and (3) those requiring major repair. All specimens were annotated to indicate that they were water damaged and the method of restoration used and then they were returned to the collection.