Proceedings e report - Firenze University Press

BIODETERIORATION OF CULTURAL HERITAGE IN ESTONIA
3.2. Wood-disfiguring fungi
As the present paper is focusing on the heritage of architecture, the problems generated by the blue
stain fungi found in fresh sawn timber and recently placed structural timber are ignored. It is the
mould that is responsible for most of the damage in buildings and items of cultural value. Due to the
lack of expertise they used to be largely neglected in Estonia till the beginning of this century although
the influx of relevant know-how from Finland and Sweden has enabled to identify damage by moulds
and take measures against it.
Moulds primarily affect items and the surface of materials in buildings in three ways. Firstly, the
materials can deteriorate due to the spread of mycelium. As the development of mould mycelium and
the amount of organic nutrients is many times smaller than that of wood-destroying fungi, destruction
of materials is a problem when the long-term conservation of materials is an issue. Secondly, the
deterioration can be induced by the pigments imparted by moulds to the surrounding materials,
whereas this damage is most substantial in art heritage because of the change in colours it leads to.
Thirdly, there is the chemical deterioration, which is instigated by the new compounds resulting from
the chemical reaction involving the substances imparted by the mycelium on the one hand and the
substances present in the surrounding materials on the other [6]. The described process can lead to the
changes in the chemical contents of the coloured surfaces.
Moulds can have ill effects on the health of the inhabitants most of which are responsible for allergy
and hypersensitivity reactions. The four types of reactions distinguished are as follows:
1. Allergic reaction whereby the spores of fungi inhaled induce the generation of antibodies. If the
person encounters the same antigens, the latter and antibodies interact and certain activating
agents released can induce symptoms like sensitive mucosa or dyspnoea.
2. Cytotoxic reaction is an allergic condition whereby the cells fight other cells of the body. This
type is of low prevalence and occurs e.g. in infants with rhesus-conflict.
3. Immune complexes are developed as a result of recurrent and frequent inhalation of antigens (the
volatile metabolites of an allergen, e.g. fungal spores or micro-organisms). [4]
4. Contact hypersensitivity due to the recurrent contact of skin with nickel, chrome etc. elements.
The powerful allergens in Estonia include some species of Cladosporium and Aspergillus, e.g.
Cladosporium cladosporoides.
In addition to causing allergic reactions some moulds produce endotoxins and mycotoxins [7] that
spread through air and cause various ill-effects. Stacybotrus chartarum (atra) is the species of mould
active in Estonia. Beetle infestation also has a substantial share among the causes of deterioration of
cultural heritage. Beside the Anobium punctatum, Anobium pertinax and Buprestis haemorrhoidalis
most widely spread in continental Estonia, the islands also have the House longhorn beetle
(Hylotrupes bajulus) (Photo 2).
Photo 2 Beetle attack in the old church in Ruhnu
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