Planteringsförbandets betydelse för kvalitetsegenskaper i Contortatall (Pinus contorta var. latifolia)

University essay from SLU/Dept. of Forest Ecology and Management

Abstract: In Sweden, large scale planting of Lodgepole pine (Pinus contorta var. latifolia) started in the beginning of the 1970’s. At first, the aim was production of pulpwood, but later, also production of timber became considered realistic. Today, Sweden has more than 520 000 ha of Lodgepole pine. Vast areas are now ready for thinning. However, the knowledge regarding forest management practices are still relatively limited. Among other studies, a master thesis shows that many properties of quality are dependant on the initial spacing. Two 20 years old Swedish spacing trials were then studied; Långsjönäset in Jämtland and Ängomsåsen in Medelpad.In this study, selected quality properties were again analysed on the same two spacing trials, now in an age of 41 years. The hypothesis was that butt logs with thinner branches, smaller relative branch diameter and smaller butt log taper are developed in more dense spacings. Another hypothesis was that initial spacing does not affect the frequency of basal- and bole sweeps and broken tops. Initial spacings of 1.60 m, 2.00 m, 2.85 m and 4.00 m were analysed. In total, 690 stems were included in the study. Butt log was identified as the first 4 m of the stem above height of the stump. Results from this study were also further compared with results from the above mentioned master thesis.For the three properties; thickest branch diameter, relative branch diameter and butt log taper, trees growing in an initial spacing of 2.85 m were of statistically significant lower quality than trees growing in a 2.00 m spacing. Between the initial spacings 1.60 m and 2.00 m no statistically significant differences could be found regarding these three quality properties. These results indicates that spacings denser than 2.00 m does not produce significally higher quality in the butt log. Only the initial spacing of 4.00 m was of statistically significant lower quality than the more dense spacings with respect to basal- and bole sweeps and broken tops. The present age of the stands is suitable for evaluation of quality properties. The results can be used as decision support concerning future management practices for stands and further industrial use of the wood.

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