Sampling and Salvaging of objects
In order to be able to carry out wood species determination or dendrochronological analyses on a wood sample / object, the object or a partial sample must be prepared in the laboratory or the necessary anatomical details are visible on the surface (non-invasive examinations).
For the determination of the wood species, a test cube of about 0.5 - 1 cm3 is usually sufficient.
For dendrochronological examinations all annual rings contained in the sample / object should be measurable, if possible. Depending on the state of conservation, different strategies are necessary:
- recent trees: cross-sections after felling, drill core extraction with the forestry increment borer
- Dry preservation (wooden elements from historic buildings): Cross-sections of wooden elements, drill core removal with milling drills
Museum objects (for example ancient Egyptian coffins), contact-free surface measurement / scanning - Preservation of wet wood: Removal of sections of the individual wood elements (keep samples wet!), Cross-section preparation with razor blade
- Charcoal: related samples shoud be packed together separately in shock and pressure resistant packages (recover samples immediately and allow to dry out slowly)
The salvage technique of whole wooden objects depends on their condition. If the piece threatens to fall apart or if meticulous detailed investigations are necessary, a block recovery is ideal since all further steps can be carried out in the laboratory. The size of the blocks depends on the object (from the charcoal piece to the well shaft). In the case of wet wood objects (for example, dugouts), salvaging is problematic because the very heavy objects easily suffer imprints / damage to the soft wood and must be kept constantly wet after salvage, in order to avoid the drying and cracking of the wood.