Mineralogy and genesis of selected soils and their implications for forestmanagement in central and northeastern British Columbia

Soil properties in central and northeastern British Columbia are strongly i nfluenced by parent materials because of geologically young till, glaciolac ustrine, and glaciofluvial deposits. We examined pedogenesis on various par ent materials to-support studies of long-term forest productivity. We sampl ed nine pedons developed on till (Bobtail, Lucille Mountain, Skulow Lake, L og Lake, Topley, and Kiskatinaw), glaciofluvial (Bowron), and glaciolacustr ine (Aleza Lake 1, 2) deposits. The Skulow Lake pedon is distinctive in the occurrence of talc, while the Lucille Mountain pedon has the only clay fra ction in which kaolinite is absent. Other pedons on till contain mica, kaol inite, chlorite, smectite, and vermiculite. The Bowron pedon has mica, kaol inite, and chlorite, while the Aleza Lake pedons have mica, kaolinite, chlo rite, and 2:1 expanding minerals. In pedons with low amount of 2:1 expandin g clays in the C horizon, mica and chlorite appear to degrade into 2:1 expa nding clays, while in pedons with C horizons containing 2:1 expanding clays , mica and chlorite seem stable and the formation of hydroxy-interlayered c lays is the predominant process. Podzolization and lessivage are major pedo genic processes, while redoximorphic processes are observed in some pedons with illuvial Bt horizons. Significant soil compaction hazards are presente d by the medium and fine soil surface textures. Although clay-rich Bt horiz ons may benefit soil nutrient regimes, conservation of nutrient-rich forest floors is important, given the low S contents in mineral soils. High conte nts of feldspars in these soils provide a large reserve of nutrients such a s Ca and K.