Stöd, R., Kilpeläinen, H. and Wall, T. 2006. Yield and Technical Quality of Scots Pine Saw Timber from Thinnings on Drained Peatlands and Mineral Soils in Finland. Baltic Forestry, 12 (2): 170-183

In this study the yield of Scots pine (Pinus sylvestris L.) timber suitable for mechanical wood processing from thinning operations in different drained peatland and mineral soil stands was determined calculatorily, using the data from field surveying. Additionally, the external quality of the trees was studied. The yield of saw timber was small in general, and its proportion of the thinning removal was modest. The largest yield was obtained when round construction timber - in addition to the normal timber assortments - was harvested. At its highest the yield of saw timber was 11 m3/ha (16% of thinning removal) from drained peatlands and 18 m3/ha (31% of thinning removal) from mineral soils. Also small-diameter and short logs increased the yield of saw timber from thinning stands as compared to the yield obtained harvesting only normal saw logs. In thinning stands the number of defect-free trees was small. The most frequent external defects were the deviations from the straight stem form. Despite the relatively poor quality of the trees, the main reason for the low saw timber yield was the small size of the harvested trees.

Key words: thinning, drained peatland, saw timber, technical quality