Effects of prescribed burning on mycorrhizal fungi in a pinus banksiana stand

Abstract

The purpose of this study was to examine the effects of fire on mycorrhizal fungi in a Pinus banksiana stand. It was hypothesized that an optimal fire intensity leads to an increase in ectomycorrhizal colonization of crop species and to a decrease in vesicular-arbuscular mycorrhizal colonization of competition species. Pinus resinosa seedlings grown in the greenhouse on soil from burned plots had significantly higher ectomycorrhizal colonization. There was no significant correlation between fire intensity and ectomycorrhizal colonization of the greenhouse P. resinosa or Pinus strobus. The P. strobus out-planted on the Clearcut and scarification and the Scarified and Prescribe Burned Treatments had significantly higher colonization than both the P. strobus out-planted in the Clearcut Treatment and the P. resinosa at all Treatment levels. There were significant levels of interactions in all of the ectomycorrhizal studies. Neither the field planted P. resinosa nor the P. strobus had a significant correlation with fire intensity. The relationship between fire intensity and vesicular-arbuscular mycorrhizal (VAM) colonization in Trifolium repens and Agrostis palustris grown and germinated on soil from a P. banksiana stand was inconclusive because the seeds from the four non-bumed plots failed to germinate. There was no significant relationship between fire intensity and VAM colonization. Burned and non-bumed field plots were examined for fungal carpophores one year after the prescribed fires. Thirty-seven fungi species were found: of these, 11 mycorrhizal fungi, nine saprophytic fungi, and two pathogenic fungi were identified. All of the pathogenic and saprophytic fungi were found on the burned plots while only two of them occurred on the non-bumed plots. Five of the mycorrhizal fungi occurred on both the burned and non-bumed plots, and two of them occurred exclusively on the non-burned plots.