Epsilon Archive for Student Projects

Abstract

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 of
lodgepole 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 those
firstly-thinned lodgepole pine stands a few years after thinning. Furthermore, the objective
was 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 at
SCA in 2008. Altogether 91 lodgepole pine stands in northern Sweden were measured after
the first thinning. Since the same stands were inventoried in 2004 and 2005, chosen results
such as thinning grade, strip-road width and the distance between strip roads were used as
additional data in correlation matrix.
It was found that:
• The average volume of dead trees in the inventoried 91 lodgepole pine stands was 3,8
m3sk/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 total
number of inventoried lodgepole pine trees.
• No correlation between the volume of dead trees and soil type, soil moisture, stands
dominant slope or stands dominant height above sea level was found. The share of the
number of dead trees gave similar results. However, a positive and significant
correlation between the share of the number of dead trees and soil moisture was found
indicating 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-road
centre was found.
• 49 % of measured stems were estimated to have sawn-timber quality. The most
frequent defect types were long crook and spike knot.