Mounding for restoration of treed peatlands; a quantitative evaluation and comparison of treatments

Some former wellsites and seismic lines in Northeast Alberta are not returning to tree cover over a decade after disturbance (arrested succession). This study tested whether intensive silviculture, in the form of mounding treatments, can resolve stagnation and accelerate return to tree cover. Larch (Larix laricina) and black spruce (Picea mariana) seedlings were planted at three former wellsites with characteristics of arrested succession, and two treatments were applied: (1) mounded plots and (2) "plant-as-is" plots. The treated plots were monitored for tree growth and survival and compared against unplanted control plots.

Growth and survival of larch and black spruce were significantly better on the mounded plots. Ingress of volunteer woody species was also significantly better on the mounded plots. These results challenge the assumption that minimal disturbance and passive management alone will lead to successful forest recovery, especially in complex peatland systems.