The comparative resistance to fungi of the wood munika (Pinus heldreichii Christ.), fir (Abies alba Mill.) and spruce (Picea excelsa Poir.) compared with Pinus sylvestris L. and some physical and mechanical characteristics of munika
M Petrovic, M Miric
The munika (Pinus heldreichii Christ.) is situated primarily in the Balkans, and partially in the south of the Apenine peninsula. As an endemic species, with a very little annual increment, it has not been used enough as a timber for mechanical conversion up till now, although the oldest trees can grow to 27 m in height, with a diameter at breast height of about 60 cm. According to data of many Balkan authors, the wood of munika can be classified as a very durable wood and resistant against almost every damaging factor, because some objects, which had been made from munika heartwood, have been in use for almost 300 years. During our research on the comparative resistance to fungi of munika wood, which was performed according to the Yugoslavian standard (JUS D A1.058), it was concluded that: -- against Serpula lacrymans, the sapwood of munika was more resistant than Scots pine (Pinus sylvestris) sapwood, because the weight loss after four months, was less in the first instance (16.7% : 20%). The heartwood of munika was practically fully resistant (the weight loss was only 0.6%). -- against Coniophora puteana, the sapwood of munika had less resistance than Scots pine sapwood (the ratio of the weight losses was 39.6% : 22.4%), while the munika heartwood was also fully resistant (weight loss was 0.7%). -- comparing munika sapwood's resistance to the above-mentioned fungi, it is obvious that Coniophora puteana: can destroy it easier and faster. It follows also that it has a different comparative resistance than that of Scots pine sapwood. Against Serpula lacrymans it had about 76.8% less activity. -- the heartwood of munika was much more resistant to the test fungi, what can be seen from the percentage weight loss. Contrasted with Scots pine heartwood, the resistance of munika heartwood to Serpula lacrymans according to weight loss was about 10 times greater, and Coniophora puteana about 6.7 times greater. -- the resistance of munika heartwood compared to Scots pine heart wood, under the activity of the above-mentioned fungi was greater for approximately the same percentages 89.8% and 85.0%.
From these results, we can conclude that the heartwood of munika is very resistant against the decay fungi (although this is not the case with its sapwood), and this is why this species can be classified in the group of the most resistant wood species. The research showed that the aforesaid characteristics were the result of the wood containing resin materials and aromatic oils. Its resistance to fungi, as well as data about certain physical and mechanical properties, primarily of its heartwood, have proved discoveries that munika can last as long as 200 years and in some specific instances for over 300 years.