Effects of Clearcutting and Slash Burning on Streamwater Chemistry and Watershed Nutrient Budgets in Southwestern British Columbia

Abstract

Two small forested watersheds near Haney in southwestern British Columbia were partially clearcut, and the slash on one of them was subsequently burned. Streamwater chemistry was monitored in these treated watersheds and an undisturbed control watershed for 2 years prior to treatment and up to 9 years after treatment. The chemical parameters that were studied responded differently to the treatments, but there was a general pattern of increased concentrations and fluxes in Streamwater for the first 2–3 years following treatment followed by a decline to, and sometimes below, pretreatment values. The most pronounced increases were observed for K and NO3. It was not possible to determine the exact causes of these changes in concentrations and fluxes, due to the great variability in the ecosystems present. This variability precluded determination of statistically significant changes in annual terrestrial nutrient fluxes and pools. Stream nutrient exports usually were <10 kg/ha/yr for each of N, P, K, and Mg, <20 kg/ha/yr for Na and Cl, and <30 kg/ha/yr for Ca. These values were considerably less than nutrient exports in harvested logs and in losses to the atmosphere during the slashburn. Clearcutting and burning caused greater nutrient losses than Clearcutting alone, particularly in the case of N, where the Clearcutting and Clearcutting and burning treatments resulted in total losses of 245 kg/ha and 1293 kg/ha, respectively, for the first two years after treatment.

Clearcut harvesting effects on soil and creek inorganic nitrogen in high elevation forests of southern interior British Columbia

“…At Sicamous Creek, increases in net NO 3 -N concentrations in clearcut soils that had occurred 2 to 3 yr after harvest were still evident in the 11th year after harvest. In other studies, elevated NO 3 levels began between 0 and 2 yr after harvest and lasted between 2 and up to 6 yr (Feller and Kimmins 1984;Hendrickson et al 1989;Dahlgren and Driscoll 1994;Hope et al 2003;Prescott et al 2003). In eastern N-saturated hardwood forests after clearcutting, nitrification under snow and leaching of the accumulated NO 3 -N may occur for up to 10 yr (Pardo et al 1995).…”

A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams

“…In most other studies, stream water chemistry has returned to pre-harvest levels within 5 years (Feller and Kimmins 1984;Reynolds et al 1995;Gundersen et al 2006), whereas nutrient export has remained elevated for a longer time (Rosén et al 1996;Ahtiainen and Huttunen 1999;Palviainen et al 2014), mostly because it takes up to 20 years until the runoff returns to the pre-cutting level (Idé et al 2013). There can be a time lag before stream water N concentrations start to rise, because N is immobilized in logging residues during the first years of decomposition (Palviainen et al 2004) and there is a delay in nitrification response (Vitousek et al 1979;Ring 2007).…”

Post-harvest nitrogen cycling in clearcut and alternative silvicultural systems in a montane forest in coastal British Columbia

“…d Assumes minimal outputs in biomass at harvesting; denitrification not included. e Based on < 0.1 kg N ha -1 growing season -1 in minimum years (2, 4 years after harvesting) and < 0.4 kg N ha -1 growing season -1 in peak years (1, 3, 5 years after harvesting) and therefore assuming < 0.2 and < 1 kg N ha -1 yr -1 as annual minimum and maximum rates, respectively; see also leaching fluxes for the first three years at the MASS site in Feller et al (2000), and other sites in Krause (1982), Feller and Kimmins (1984), Kimmins et al (1985), Martin and Harr (1989), Jewett et al (1995), Titus et al (1998). f Minimum balance assumes minimum input minus maximum output.…”