Forest Investment Account

Abstract of FIA Project 2214004

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Testing the Biological Effectiveness of Mechanical Site Preparation 17 year results

Author(s): Bedford, Lorne
Subject: British Columbia, Silviculture/Forest Management Systems
Series: Forest Investment Account (FIA) - Land Base Investment Program - Innovative


Nine site preparation techniques for re-establishing productive lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) forest in the Stuart Dry Warm Sub-Zone of the Sub-Boreal Spruce Zone (SBSdw3) of interior British Columbia on 'NSR backlog' (i.e., by provincial criteria, not-sufficiently-regenerated) sites are compared in a randomized block experiment, with one 48-tree, 750-m2 plot of each treatment in each of 5 blocks. Low fertility, compact subsoil, and low water-holding capacity in a rooting zone as thin as 10 cm in lower slope and level positions are the main limiting factors. After 10 growing seasons, pine survival was 90-97%; mean stem volumes in 7 treatments were 41-235% higher than the control, and one treatment gave 29% less volume. Results from mounding and patch scarification were virtually identical. While site preparation can increase early growth of lodgepole pine, especially on the more poorly drained parts of sites such as Bednesti, planting directly into sheared, windrowed ground will give satisfactory survival and growth.Detailed measurements of microclimatic data and tree growth have been maintained for the past 6 years and will be summarized in a journal article to be prepared in the next year.

For further information, please contact John McClarnon, BC Ministry of Forests (

Updated September 08, 2005 

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