Lodgepole pine - stability after thinning

Sammanfattning: SCA has today almost 300 000 hectares of their forest land planted with lodgepole pine(Pinus contorta var. latifolia). Due to initial extensive planting in the 1970ies the area oflodgepole pine forests in the thinning age has grown rapidly from the end of the 1990ies.During the years 1996-2005 first commercial thinning of lodgepole pine at SCA took place.The goal of the hereby presented study was to investigate the growth and stability in thosefirstly-thinned lodgepole pine stands a few years after thinning. Furthermore, the objectivewas to investigate the relationship between stand stability and different stand parameters.Additionally, lodgepole pine stem quality was estimated.The study is mainly based on the data collected during an inventory project carried out atSCA in 2008. Altogether 91 lodgepole pine stands in northern Sweden were measured afterthe first thinning. Since the same stands were inventoried in 2004 and 2005, chosen resultssuch as thinning grade, strip-road width and the distance between strip roads were used asadditional data in correlation matrix.It was found that:• The average volume of dead trees in the inventoried 91 lodgepole pine stands was 3,8m3sk/ha being equal to 2,3 % of the standing volume at the time of the inventory.• In terms of the number of trees, dead trees formed on average 3,9 % of the totalnumber of inventoried lodgepole pine trees.• No correlation between the volume of dead trees and soil type, soil moisture, standsdominant slope or stands dominant height above sea level was found. The share of thenumber of dead trees gave similar results. However, a positive and significantcorrelation between the share of the number of dead trees and soil moisture was foundindicating higher risk for damages on wet soils than on dry soils.• Risk for mortality after thinning increases in stands thinned at larger dominant height,stands with high thinning grade and wide strip-roads.• No clear relation between types of dead trees and their distance to the closest trip-roadcentre was found.• 49 % of measured stems were estimated to have sawn-timber quality. The mostfrequent defect types were long crook and spike knot.