Soil reclamation and reforestation at oil and gas well sites in northeastern British Columbia.

摘要

With over 1,400 oil and gas wells drilled in northeast British Columbia (BC) in 2005 alone, cumulative reductions in future timber supply may occur if well sites (~1 ha in size) are not reforested. Well sites resemble forestry landings in their challenges to soil productivity and reforestation, which include adverse physical conditions (i.e., compact soils), low organic matter content, and limited nutrient supply. Previous research in BC on forest soil rehabilitation techniques has developed practical methods for ameliorating adverse soil physical, chemical, and biological conditions in forestry landings. This project focused on the application of these techniques to typical abandoned well sites in the Peace River region of BC as part of achieving successful reforestation. Five abandoned well sites were selected within the Boreal White and Black Spruce biogeoclimatic zone near Fort St. John and Dawson Creek, BC. Treatments consisted of tillage, wood chip mulch, tillage + wood chip mulch, tillage + incorporated wood chips, brush mats, and an untreated control. Treatments were implemented between fall 2003 and spring 2004, and sites were subsequently planted with alternating seedlings of lodgepole pine (Pinus contorta var. latifolia Dougl. ex Loud) and white spruce (Picea glauca [Moench] Voss). Soils at all sites were fine to medium in texture with average coarse fragment contents ranging from 3% to 10%. Soil conditions were monitored throughout the 2004 and 2005 growing seasons. Response variables include soil physical parameters (bulk density, soil mechanical resistance, moisture content, air-filled porosity, water retention characteristics), nutrient availability, and seedling survival and growth. Soil physical property data (i.e., soil mechanical resistance, air-filled porosity, and water retention) indicated soils on control plots were in a potentially physically degraded state with respect to theoretical growth-limiting thresholds. These results suggested they were good candidates for rehabilitation. Treatme