Analysis of sound velocity through the wood of spruce trees lacated into a burned area

Abstract

In the world the effects that forest fires have on the quality of the wood and the vitality of the standing trees are a very important topic. Thus, the purpose of the article aims to analyze the transfer of sound waves through the wood of standing spruce trees (Picea abies (L.) H. Karst.) after a forest fire. The investigations were carried out in a spruce forest located in the Postăvarul Mountains area where, in 2012, there was a fire, which affected about 22,5 ha of forest and was extinguished after almost a month, due to the difficult area and the peculiarities of the fire. The measurements were made with the Arbotomtomograph. 6 spruce trees were investigated, of which 4 trees affected by the fire, a dry tree due to the wounds suffered and a control tree, located in the buffer area. There were made two measurements for each tree, one at a height of 50 cm from the ground level, and the second at 100 cm. The tomograms obtained were interpreted and it turned out that the trees present, inside, areas with affected wood, centrally arranged, but also marginal, especially at the first level analyzed. Also, it was found that some trees showed no signs of internal unevenness, or these areas are very small in size. In addition, it was observed that the trees had different vitalities, many of them being in drying process, which was proven by the appearance of the drying of the tip in some specimens. Following the interpretation of the tomograms it turned out that the control tree, even though it does not have any external sign that attracts attention, has inside an extended area where the characteristics of the wood are strongly modified, compared to the trees affected by the fire. At the dry tree, it was observed that the affected area had a tendency to advance towards the outside of the section where there was no bark, being a vulnerable area, the unaffected wood being dry, but healthy.