Unrecorded volume of Norway spruce timber in cut-to-length harvesting

摘要

Knowing credible records of harvested timber is in the interest of the forest owner, forest entrepreneur and timber-sector stakeholder. Therefore, the objective of the research was to determine the share of unrecorded Norway spruce timber volume in length allowance on the total timber volume produced by harvester technology in Czechia. We analyzed 176,980 merchantable logs (total volume of 10,333 m(3)) produced by 15 harvesters. Primary data were obtained from .stm files. Logs were categorized into five grades according to metric and qualitative requirements of the customers, also butt logs were distinguished. Statistical analysis were processed in the Statistica 13 package. Results showed that 1.99% of the volume of produced timber were excluded from the primary forestry records. Mean unrecorded volume of length allowance to assortments that contained both the cross-cut and cutting window allowances, varied from 2.99% up to 3.16%, while 0.27% to 0.46% of volume were unrecorded for those assortments that contained only the cutting window. In higher quality grades, we found shorter logs had a higher mean relative volume of length allowance than longer logs. The mean relative volumes of length allowances also varied between butt and other logs.