Growth following selection harvesting of dry-belt Douglas-fir (EP 987.04)

Introduction

This study was established in 1993, in cooperation with the Vernon Forest District, to provide information on the response of uneven-aged, dry-belt Douglas-fir to partial cutting. The installation is established in a multi-aged, mid-climax Douglas-fir stand with minor components of lodgepole pine, interior spruce, trembling aspen and paper birch, within the Cascade variant of the Dry Cool Interior Douglas-fir biogeoclimatic subzone (IDFdk2) north of Westwold.

Objectives

To determine the effects of different levels of residual growing stock and stand structure on the growth and yield of dry-belt Douglas-fir following single-tree selection harvesting.

Treatments

Factorial combinations of three levels of residual basal area and two levels of stand structure ('q' values) are being tested, along with an untreated control. The three levels of residual basal area are 15, 20, and 25 m2/ha. The stand structure factor (q) is the negative exponential constant between 5-cm diameter classes with two levels (1.3 and 1.5). For all treatments, the maximum tree-size goal was 50 cm, and the treatments were applied to that portion of the stand between 7.50 and 52.49 cm in diameter at breast height. The partial cutting treatments removed between 33% and 60% of the initial basal area from treatment plots. All cut trees were yarded to the road-side by horses in order to minimize damage to the residual stand.

Each of three replicate blocks contains all six of the partial cutting combinations, plus an untreated control. Treatments were randomly assigned to plots within each block. All of the treated and control plots are 0.25 ha (50m x 50m) in size. The installation is re-measured every 5 years.

Publications

• B.C. Ministry of Forests publications can be downloaded from the following website:
  http://www.for.gov.bc.ca/scripts/hfd/pubs/hfdcatalog/index.asp

Bealle Statland, C. and W.D. Johnstone. 2004. Natural regeneration 10 years after partial cutting in a dry-belt interior Douglas-fir stand. B.C. Ministry of Forests, Victoria. Extension Note 68.

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Last Modified: 2007 APR 20.  Ministry contact: Frank van Thienen
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