Canadian Forest Service Publications

Response of white spruce plantation to three levels of thinning from below 1958-1978. 1980. Stiell, W.M. The Forestry Chronicle 56(1): 21-27.

Year: 1980

Issued by: Pacific Forestry Centre

Catalog ID: 4551

Language: English

Availability: Order paper copy (free), PDF (download)

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Abstract

In 1958 a thinning experiment to examine the relation of stand growth of white spruce (Picea glauca (Moench) Voss) to density of residual growing stock was established at the Petawawa national Forestry Institute in a 33-year-old plantation growing on a sandy old-field site. A treatment series consisted of sample plots thinned from below to basal area levels of 18.4, 25.3 and 32.1 m2/ha, together with unthinned plots serving as controls. Two such replicates were established. The plots were remeasured and thinned again to the prescribed basal areas in 1968 and 1978. Diameter growth and form quotient were clearly related to degree of thinning. Volume growth was reduced at the lowest residual basal area. The untreated plots contained the highest volume in 1978 but mortality had reduced their total production of merchantable wood by about 10% compared with the thinnings plus standing crop of the two lighter treatments. Thinning to leave a basal area in the range of about 22 to 35 m2/ha should yield 11 to 60 m3/ha of merchantable wood, depending on plantation age and intensity of cut, without reducing stand growth.