Contribution to study of changes in split-firewood density of European beech (Fagus sylvatica L.) due to air drying

U radu su eksperimentalno i teorijski istraženi utjecaji parametara vlage, mase, volumena i gustoće cijepanog ogrjevnog drva zbog velikog značaja na komercijalno poslovanje takvim drvom. Istraživanje je provedeno na uzorku od 13 komada cjepanica. Cjepanice su izrađene u jednom specijaliziranom proizvodnom pogonu mehaniziranom tehnologijom uz korištenje motorne lančane pile i hidrauličkih cjepača. Svaka cjepanica je za potrebe istraživanja izmjerena i obilježena brojem, te je na njima provedeno mjerenje mase, dimenzija i vlage u sirovom i prosušenom stanju. Prirodno sušenje izvedeno je na zaklonjenom i dobro provjetrenom dijelu stovarišta cijepanog ogrjevnog drva. Sušenje cjepanica je trajalo u vremenskom periodu od 20.3.2015. do 12.10.2015., odnosno ukupno 206 dana. Prosječan sadržaj vode u cjepanicama prije sušenja iznosio je 66,020%. U prosušenom stanju, prosječan sadržaj vode u cjepanicama iznosio je 21,070%. Prosječna vrijednost mase cjepanica obzirom na sve izmjerene cjepanice u sirovom stanju iznosila je 14,723 kg, a u prosušenom stanju je ta vrijednost smanjena na 10,938 kg. Gledano obzirom na sirovo stanje, gubitak u masi iznosio je prosječno 25,71% U sirovom stanju, aritmetička sredina volumena svih cjepanica iznosila je 0,01427 m, dok je u prosušenom iznosila 0,01256 m. Gledano obzirom na sirovo stanje, smanjenje volumena iznosilo je prosječno 11,98%. Aritmetička sredina za gustoću cjepanica u sirovom stanju iznosila je 1022,68 kg/m, a za prosušeno stanje iznosila je 870,62 kg/m. Gledano obzirom na sirovo stanje, smanjenje gustoće iznosilo je prosječno 14,86%.This paper focuses on the research of experimental and theoretical influences of parameters such as moisture, mass, volume and density of split firewood due to its great importance in firewood sales business. The study was conducted on a sample of 13 different splits. The splits were produced in a specialized production facility using mechanized technology which includes the use of chainsaws and hydraulic splitters. Each split in this research was measured and numbered, along with the measurements of mass, proportions and moisture in both raw and dry state. Natural drying was performed in a sheltered and well-ventilated area of the warehouse intended for split firewood. The drying process lasted for 206 days, in the period from March 20, 2015 until December 10, 2015. The average water content in the splits before the drying process was 66,020%. In the dry state, the average water content was 21,070%. The average value of the measured mass of the raw splits was altogether 14,723 kg, and in the dry state, this value was reduced to 10,938kg. The average mass loss in the raw state amounted to 25,71 %. In the raw state, the arithmetic average of the volume of the splits was 0,01427 m, while in the dryed state it amounted to 0,01256 m. In the raw state, the average volume reduction amounted to 11,98%. The arithmetic average of the density of the splits in raw state was 1022,68 kg/m, and for the dry state 870,62 kg/m. In the raw state, the average density reduction amounted to 14,86%