Conservation of Ancient Timbers from the Sea 287
probably worth aiming for a storage period of less than 12 months. This is not
always possible when dealing with a well-preserved marine wreck site that
can provide many tons of well-preserved waterlogged wood. In such cases,
storage periods of up to 20 years are not uncommon.
During storage, waterlogged archaeological wood is subject to attack by
bacteria, fungi and insects. To prevent such biodeterioration in waterlogged
archaeological wood, a storage method should be employed which must ful-
fil the following criteria: (i) maintain maximum moisture content; (ii) prevent
or minimise further decay; (iii) be compatible with subsequent studies and
treatment method; (iv) be easy to maintain; (v) be inexpensive; and (vi) must
be non-toxic for conservators who maintain it and subsequently work on it.
Of greatest importance is that the wood will always be kept water saturated
from the time of recovery until conservation treatment begins. Numerous
methods have been employed to store waterlogged archaeological wood:
(i) wrapping in polyethylene bags,
(ii) immersion in tanks containing water,
(iii) spraying with water, and
(iv) keeping wood buried in anoxic sediments.3.4 Wrapping in Polyethylene Bags or Sheeting
The most commonly used method of storage is wrapping wooden artefacts or
individual ships’ timbers in polyethylene bags of various sizes. Polyethylene
sheeting is often used and all edges are hermetically sealed to prevent the dry-
ing of the stored artefact. Wrapped wooden artefacts are often kept within
buildings where there is no temperature control. Maintaining the waterlogged
state of the wooden artefact or timber is an important criterion and should not
be underestimated. If wood is maintained in a waterlogged condition, the
growth of wood-rotting fungi may be restricted since water saturation will
limit the amount of available oxygen that is required by the fungi. However,
low oxygen tensions may not totally prevent the growth of certain fungi, espe-
cially soft rot fungi. These fungi are better adapted to decay wood in conditions
of low oxygen tensions, since they preferentially degrade cellulose through a
non-oxygen process. Examination of polyethylene-wrapped Mary Rose tim-
bers has been demonstrated to support wood decay microorganisms. Fruiting
structures of 17 fungi were found on the surface of timbers. Three of these
were terrestrial fungi and 14 were marine fungi (see Table 1). The most fre-
quent species was M. pelagica recorded on 23% of timbers examined.
Despite the large number of wood-decay fungi growing on the surface of
stored timbers, few signs of recent attack were observed. Soft rot cavities were
observed but were not numerous. Such decay patterns were only observed