Contents variability of total phenols in wood of trunks and knots in common beech

Raziskovali smo variabilnost vsebnosti celokupnih fenolov v lesu debla in grč navadne bukve (Fagus sylvatica). Drevesa smo posekali v Kočevskem Rogu, izžagali vzorce, jih zmleli in pripravili za ekstrakcijo, opravljeno z napravo po Soxhletu in uporabo cikloheksana in metanola. Z UV-Vis spektrofotometrijo smo določili vsebnost ekstrahiranih snovi ter vsebnost celokupnih fenolov. Najmanjši delež celokupnih ekstraktivov je imelo drevo številka 3 ( 1,82 %), največ hidrofilnih ekstraktivov pa drevo številka 6 (55,53 mg/g). Kategorija lesa je ključni vir variabilnosti v vsebnosti ekstraktivov znotraj drevesa. Najmanj celokupnih ekstraktivov je bilo v rdečem srcu (1,86 %), največ hidrofilnih pa v živi grči (65,75 mg/g). Pri vseh preučevanih drevesih je bila vsebnost celokupnih fenolov v poranitvenem lesu večja kot v beljavi.We studied variability of total phenols in wood of trunks and knots of common beech (Fagus sylvatica). Tree samples were cut in Kočevski Rog. The extraction was done using Soxhlet device with cyclohexane and methanol. The content of extracted substances and the content of total phenols were determined using UV-Vis spectrophotometry. The lowest total extractives portion of phenols was found in tree No. 3 (1,82 %)the highest content in hydrophilic extractives was in tree No. 6 (55,53 mg/g). The wood category is the key source of variability in the content of extractives within the tree. The lowest portion of hydrophilic extractives was found in red heart (1,86 %), the highest in living knots (65,75 mg/g). In all studied trees the amount of total phenols was higher in wound-wood than in sapwood