Establishing white spruce in the Boreal White and Black Spruce Zone Site preparation trials at Wonowon and Iron Creek, British Columbia

Abstract

Two trials (``Wonowon'' and ``Iron Creek'') in the Prince George Forest Region of interiorBritish Columbia were begun in the mid 1980s toevaluate site preparation treatments for establishingwhite spruce (Picea glauca [Moench] Voss) in theBoreal White and Black Spruce biogeoclimatic zone. The14 treatments (9 or 10 per trial) were: [B.C.]Ministry, Sinkkila, and Bracke mounds; Bracke moundsmanually supplemented with 20-, 14-, or 6-cm cappingsof mineral soil; fertilized Sinkkila mounds; Brackepatches; fertilized Bracke patches; bladed strips;plowed ground; herbicide; and untreated controls,separately with both standard and nominally superior``alternate'' planting stock. With minor aberrations,each trial consists of 5 randomized complete blockseach with one 80-tree plot per treatment; planting wasin spring, 1984 at Wonowon, 1987 at Iron Creek. Alltrees in mounding treatments and the inner 48 trees inother plots were monitored for performance through1998 at Wonowon, 1996 at Iron Creek. The herbicide andplowing treatments, and mounds capped thickly enoughwith mineral soil to inhibit weed regrowth, wereclearly superior to others. In the mounding treatments at Wonowon, survival rateincreased with capping thickness, but, while the 14 and 20 cmcappings were best, significant differences among them were few after 15 growing seasons.In both trials, patchscarification gave poorer results than did plantingwithout site preparation.