Determining Harvester Productivity Curves of Thinning Operations in Birch Stands of Central Europe

Silver birch (Betula pendula Roth) is a popular tree species forming stands in nearly the whole of Europe. In Poland, one most representative broadleaved growing on rather poor soils, very often as mix with Scots pine (Pinus sylvestris L.). Central Europe, forms trunk sweeps, and at older age thick branches. Due to that, harvester thinning operation can be challengeable when trying process logs from top part trees, which finally impact productivity. The objective this research was determine productivity for particular attention production tree. carried out North North-West Poland. All together 21 tests were completed 16 stands, 9 harvesters used (8 different models). mean diameter harvested trees 23.7 cm height 21.7 m. Obtained without delays average 21.98 m3 h-1 varied low 5.14 maximum 44.66 h-1, depended mainly size. It also confirmed that last log breast (DBH). model developed based relationship prediction biomass volume are thinning.