Effect of clearcutting, selection cutting, shelterwood cutting and microsites on soil surface CO2 efflux in a tolerant hardwood ecosystem of northern Ontario

The effect of clearcutting, selection cutting, shelterwood cutting and microsites on soil surface CO2 efflux (SSCE) evolution was evaluated in a tolerant hardwood forest ecosystem in northern Ontario from May to November, 1998 using a LI-6200 dynamic, flow-through, portable, infrared CO2 gas analyzer. Selection and shelterwood cutting had the greatest effect, decreasing SSCE in September and October compared to control. SSCE from clearcut plots were intermediate between the control and other treatments. SSCE correlated strongly with soil temperature and weakly with soil moisture. Comparison of microsites disturbed by harvesting with those left undisturbed showed that SSCE was significantly lower on scarified microsites than on undisturbed microsites. Our results emphasize the importance of microsite distribution within harvested or otherwise treated areas, and may explain some of the discrepancies between several studies on the effect disturbed ecosystems have on SSCE.