esteng

The project "Fungi and Beetles in Buildings on Islands of Baltic Sea”

 

Attacks of wood destroying insects and wood decaying fungi make the conservation of wooden buildings problematic for islands and coastal regions. The spread of beetles and fungi is much more extensive on the islands and in coastal regions and the damages caused by them is much greater because of favorable climate conditions. Additionally, the population of beetles has grown so much on Ruhnu Island because of its closed ecosystem.

Previously, architect T. Parmakson and engineer A. Danil have studied the condition of wooden constructions of the new  Ruhnu church. They used several methods: visual observation, knocking with the axe and drilling. Parmakson and Danil concluded, from their investigations held in 1997, that the wooden constructions of this new church are dangerous.

Before project writing, we did additional fieldworks on Ruhnu Island five times. Our aim was to determine the extent of  attacks of fungi and wood destroying insects and analyse the remaining cross-section and strength of timber structures. Kalle Pilt (from Estonian University of Life Sciences) and Kristel Pau (from Estonian Mycology Research Centre Foundation) studied the damage  caused by wood destroying insects in both churches in autumn 2007. Results of this investigation were presented at a joint meeting of COST Action IE0601 Wood Science for Conservation of Cultural Heritage in Braga, Portugal in 2008. This presentation aroused the curiosity of dr Uwe Noldt, an expert in wood destroying insects in Germany, in Ruhnu churches. With dr Noldt we made another investigation in Ruhnu churches in 2009. A detailed review was written on the condition of both churches. In the same year, the third fieldwork was done and this time, in addition to the above-mentioned experts, dr Ilze Irbe, a specialist from the Latvian State Institute of Wood Chemistry, participated and investigated fungal damages in these churches and also in Korsi farm building.

In addition, Merilin Melesk, a student from the Estonian University of Life Sciences, did fieldworks on Ruhnu Island (in July and October 2008) and wrote a Master’s thesis on the evaluation of timber structures with beetle damage of the new church tower on Ruhnu Island (supervisor Kalle Pilt). Melesk concludes in her thesis that the main insects causing damage in Ruhnu church are the following: house longhorn beetle(Hylotrupes bajulus), furniture beetle (Anobium punctatum) and death watch beetle (Xestobium rufovillosum). Various measurements showed that two timber structures of the steeple were in bad condition. For example, the measured timber structures had lost 15.4% of their cross-section.Melesk also concludes that wind speed up to 45 m/sec can cause a chain reaction with wooden structures in the church steeple, so that the steeple collapses.

 

The above-mentioned fieldwork led to the understanding that other wooden buildings on Baltic Sea islands should also be investigated. We found that the attacks of fungi and wood destroying insects in buildings are more numerous on islands than in the Estonian mainland. After discussions with the Estonian Swedish Minority Cultural Council and the Estonian Ministry of Culture we decided to write a project to the Central Baltic INTERREG IV A Programme Islands Sub-programme. The aim of this project is to prolong the durability of wooden buildings and structures on islands so that the historically valuable architectural heritage and properties of people are preserved. Several experts from Estonian, Swedish, Latvian and German universities take part in this project and their main aim is to work out an environment-friendly and sustainable methodology for the treatment of fungal and beetle damage in timber structures. At the same time, an example treatment will be performed in Ruhnu churches. So far, entomologist dr Uwe Noldt has proposed  thermal treatment. This treatment has been previously used in German churches.

The lead partner in this project is the Estonian Open Air Museum, head  of which is Elo Lutsepp, the project manager for rural architecture. The manager of the present project is Kalle Pilt who is also the author of the idea of this project. The first positive feedback came on 13th October, 2010 from the Central Baltic INTERREG IV A Programme, Islands Sub-programme. The final approval came in January 2011.