 Many industrial branches developed in that time, like forestry and wood industry (stave fabrication, the production of potash, lumber mills, shipbuilding).The most profitable one was stave fabrication, the boom of which started in the 1820s with the clearing of the oak forests around Karlovac and Sisak and again in the 1850s with the marshy oak masses along the Sava and Drava rivers.Shipbuilding in Croatia played a huge role in the 1850s Austrian Empire, especially the longe-range sailing boats.