Obecność martwic na pniach drzew stojących a jakość i wartość surowca dębowego

This paper aimed to evaluate the impact of necroses occurring on trunks of standing oak trees on their wood quality and value. The research was carried out in five study plots situated in the Meszcze Forestry, Piotrków Forest District (central Poland). The investigations covered: measuring the diameter at breast height of every injured tree with diameter ≥7 cm, estimating the length of the trunk fragment that should be cut off to remove the defect, the assessment of the quality and size of the 3−m butt−end fragment of a trunk, excluding the detected damage or rot (classification I), as well as the quality and size assessment of the same trunk fragment, though including the encountered defect (classification II). The theoretical volume of timber within the particular quality classes was computed (WAt, WBt, WCt and WDt). Afterwards, the real volumes (WAr, WBr, WCr and WDr) were compared with those of groups S2r and S4r. Based on the analysis of the quantity of damaged trees in the investigated trial plots, the lowest share of such specimens was recorded in the compartment 2a (1.6% of defective trees). Whereas, the highest share of damaged trees was encountered in the compartment 39a (8.5%). The timber of more valuable large−sized classes 'migrated', due to damages, to the groups of medium−sized timber (S2 or S4). With respect to the total volume of timber within the particular classes and groups, the greatest loss was reported in the WB class. The timber in question 'migrated' mostly to the group S2, though a part of it was classified to the group S4 as well. The established decrease in the timber value, due to damages to trunks, accounted for ca. 26%, which amounted to ca. 5.8 thous. PLN, in relation to the entire investigated material. The obtained results indicated the necessity to reduce the damages occurring in oak stands and remove the injured trees as soon as possible to avoid a significant depreciation and a value loss of raw wood.