Proceedings e report - Firenze University Press

BIODETERIORATION OF CULTURAL HERITAGE IN ESTONIA
Kalle Pilt*
Estonian University of Life Sciences, Department of Rural Building, Tartu Estonia
Abstract.
There are about 5000 buildings of some historical value in Estonia with more than 90% of them involving
wooden elements or timber structures. The present paper provides data obtained by a large-scale survey of
hundreds of buildings of cultural value to assess the extent of fungal decay. The survey found the dry rot fungus
(Serpula lacrymans) to be the most invasively spread fungus that buildings all over Estonia have been infested
by. Coniophora puteana is the second most widely spread fungus, though it’s significantly less invasive than
S.lacrymans. Beside the above two fungi, Leucogyrophana spp., and Antrodia spp. are extensively present in
Estonia. In addition to wood decay fungi, there are moulds that can also attack buildings and elements of cultural
value. Although the mould used to be largely neglected in Estonia due to the lack of expertise, since the import
of the relevant know-how from Finland and Sweden the moulds such as Aspergillus spp., Cladosporium spp. and
Penicillium spp. have been identified and counter-measures are being taken. The insect damage was also found
to be rather extensive. While in the continental Estonia Anobium punctatum, Anobium pertinax and Buprestis
haemorrhoidalis are the most widely spread, the islands have a fourth species, i.e. Hylotrupes bajulus as well.
Further studies will involve measuring the strength of structural timber, assessing the extent of fungal decay and
elaborating recommendations for renovating the buildings of cultural value. The results of the study can be
applied by the renovation companies and the administrators of the buildings of cultural value.
Keywords: Cultural Heritage, Dry rot, Wood-destroying fungi, Wood-disfiguring fungi, Serpula lacrymans,
Coniophora puteana
1. Introduction
As of 01.10.08, 23 931 items, including 12 966 items of arts heritage, have been officially registered
as items of cultural heritage of the Republic of Estonia (See the classification in Fig. 1). The majority
of the items of arts heritage are deposited in and protected by museums and arts depositories, with
KUMU in Tallinn being the largest among them. While the depositories have the facilities to maintain
appropriate conservation conditions and major problems with biodeterioration can be prevented, the
items of architectural heritage (5277 in total) run the highest risk of biodeterioration. Across the
centuries, timber and limestone have featured as the main building materials in North, North-East and
West Estonia (including islands), and stones and clay in Central and South Estonia. Therefore, in most
of the buildings timber is either the material applied throughout or in certain parts of the building,
while pine and spruce as the species indigenous of this latitude are the most frequently resorted to. The
main types of deterioration include the fungal attack, beetle infestation and chemical and physical
change [1] of which the present paper addresses the first two detected in the timber parts and elements
of 938 buildings (including 136 items of architectural heritage) surveyed in Estonia in 1999-August
2008.
The fungal attack can be caused either by wood-destroying fungi or by wood-disfiguring fungi [2].
Although the surveyed timber items of cultural heritage featured both of the above types, the former
appears to be substantially more destructive. The wood-destroying fungi can be further divided into
basidiomycete wood-rotting fungi and soft rot fungi, and the wood-disfiguring fungi into bluestain
fungi and moulds, respectively [2]. In addition to the fairly rough classification described, Schmidt
(2006) in ”Wood and Tree Fungi” provides a more complex taxonomy which distinguishes between
wood rot fungi including Brown Rot, White Rot and Soft Rot, and wood discoloration fungi including
Moulds, Bluestain and Red streaking, respectively [3].
* E-mail: Kalle.pilt@emu.ee
Joseph Gril (edited by), Wood Science for Conservation of Cultural Heritage –Braga 2008: Proceedings of the International
Conference held by COST Action IE0601 (Braga - Portugal, 5-7 November 2008, ISBN 978-88-6453-157-1 (print)
ISBN 978-88-6453-165-6 (online) © 2010 Firenze University Press