Zmiany zachodzące w lasach Beskidu Małego

Like in the Beskid Śląski and Żywiecki Mts., the dieback of Norway spruce stands takes place also in the Beskid Mały range. This process is clearly more intensive and occurs over a longer period of time. The conversion of these forests during the study period (2004−2016) resulted in a significant increase in the proportion of beech and fir as well as other, mostly deciduous tree species (tab. 1). The dieback of spruce forests is likely to continue, as the share of spruce in some forest complexes is still high. The age class structure of forests during the study period was found to have a negative effect on the stability and uniformity of forest growth – the young stands fraction was too low and decreased (tab. 3). The high average age of stands, which increased from 67 in 2007 to 71 years in 2016 was also unfavourable. The volume of harvested timber was rather high and approximated to the volume of allowable cut determined by the stand growth model (so−called model volume) (figs. 1, 2). In the Andrychów Forest District the harvested volume was significantly lower than the model volume, while in Jeleśnia and Bielsko districts it was significantly higher, which results from higher proportion of spruce in these regions. In the harvested timber structure, the share of wind−broken and wind fallen trees was about 10%, which is not high for the mountain area (fig. 3). The exception was in year 2005, when timber removals after the hurricane of November 2004 were estimated at more than 30%. In 2006−2008, the volume of deadwood was high and consisted mainly of spruce (fig. 4). Then the dieback of spruce forests decreased and was observed predominantly in the western and southern parts of the forest complex. The years 2013−2016 saw a high share of live trees in the harvested timber volume (over 80% of the model volume) (fig. 5). In some parts of the Beskid Mały forests, the harvest of live trees exceeded 300% of the model volume. Such high harvest is justified by the need of urgent silvicultural tasks to be carried out, especially stand conversion. The threat to the Beskid Mały forests from wind is high and remained at the same level throughout the study period – the threat measure Ms was ca. 33 (fig. 6). It is essential to lower the level of threat to these forests by, inter alia, increasing the area of young stands.