EFFECT OF SITE PREPARATION ON THE NUTRIENT CONTENT OF NONCROP VEGETATION IN A JACK PINE CLEAR-CUT

The nutrient (N, P, R, Mg, and Ca) content of the aboveground living n on-crop vegetation of a jack pine (Pinus bank;banksiana Lamb.) clear-c ut in eastern Ontario was investigated for two years after site prepar ation, which consisted of prescribed burning under different fire inte nsities and disk trencher scarification. Total plant nutrient content generally followed biomass accumulation with higher levels of plant N, P, Ca, and K in clear-cuts and scarified sites than in burned-over si tes. In the first growing season, concentrations of N, P, and K were h igher in the vegetation of burned-over plots than in scarified and cle ar-cut plots. Mg concentrations were greater in burned-over and scarif ied plots than in the clear-cut plots. Ca concentrations did not diffe r among the treatments. Concentration of P and K and the total amount of N, P and K in aboveground non-crop vegetation were correlated well with fire intensity at the end of the first growing season whereas onl y K concentration and quantities were correlated to fire intensity wit hin two years after treatment.