The aim of the research was to determine the changes in susceptibility of Scots pine (Pinus sylvestris L.) wood to feeding by subterranean termites Reticulitermes lucifugus var. santonensis conducted in accordance with the ASTM D 3345-08: 2009 The sapwood after modification in furfuryl alcohol at concentration 50% with the addition citric acid at concentration 1%, natural sapwood and heartwood experiment as a compulsory reference material were used for the tests. The blocks of Scots pine wood were used to create seasoned samples of 7% ± 1% moisture content. The blocks with dimensions of 25.4 x 25.4 x 6.4 mm were made from three trees. Each variant was represented by 5 blocks. All wood blocks were freeze-dried before starting the experiment in order to measure the dry weight. After 4 weeks of termite feeding visually rates of wood destruction were: 9 (light attack) for modified sapwood, 2.8 (heavy attack/failure) for natural sapwood and 8.2 (light attack/moderate attack) for natural heartwood. The loss of wood weight of blocks was: 0.01 g for modified sapwood, 0.071 g for natural sapwood and 0.21 g for natural heartwood. The mortality of the termites in the case of modified sapwood was complete. The termite mortality in natural sapwood has been classified as slight, and in natural heartwood as slight to complete.
Comparative research was conducted on shear strength parallel to grain of heartwood of Scots pine (Pinus sylvestris L.) from the 16-18th century from Central Poland and of modern wood. Tests were performed on 150 samples of aged wood from 13 construction elements of 4 historic buildings and on 100 samples from 10 modern constructional elements. Aged wood revealed a better technical quality. The difference of average shear strength parallel to grain values equaled 0.09 MPa and the translation of correlation line was about 0.35 MPa in favour of aged wood.
Scots pine wood (Pinus sylvestris L.) is the most common wood material used in historical buildings in many parts of Central and Eastern Europe. Experiments were conducted natural aged wood (263 – 459 years old), extracted from construction elements of four historical buildings (from seven construction elements), and contemporary wood extracted from 5 construction elements. A strong relationship was observed between density and static bending strength (MOR) of natural aged wood (R2 = 0.5599), and also of contemporary timber (R2 = 0.7863). Antique wood compared to contemporary wood with the same average moisture content and density is characterized by significantly lower modules (static and dynamic), the speed of ultrasonic waves transitions, and bending strength. Differences in these properties increase with increasing wood density.