Quality Variations in Logging Residues - Southern Sweden

1989

76 S.

11 Abb., 19 Tab., 10 Anh.

Bandaufführung

2044

34003

During the productin season of 1988, the quality of logging residues in the south of Sweden was evaluated. Altogether material from 107 felling sites including 33 sites of softwood and 52 sites of hardwood was analysed. The results showed that the 10 best high quality samples of both hardwood and softwood came from one single region and that they were delivered by the sme contractor. The material from hardwood that was dried during summer maintained good quality during winter. The quality of logging residue of softwood in general declined if the chipping was delayed until winter. This was the case irrespective of the storage method; heaps or windraws. The highest moisture content measured in both assortments was correlated with the thawing of snow. Material with high moisture content also showed high ash content, which would indicate degradation of the material. High precipitation corresponded strongly to high moisture content in logging residues of softwood. The strongest correlation was found to a period of one month. The statistical calculation also showed that 50 mmm of precipitation the month before chipping reduced the acceptable ships fraction (7-45 mm) by 5 per cent units. A similar effect was noticed when the material was stored for a period of 6-7 months.