Evaluation of Forest Reclamation Efforts on Linear Corridors of the Little Smokey

Tim Vinge
Victor Lieffers
Resource Date:

Linear corridors created for access during industrial development leave a large footprint on forested landscapes. In this work we examined the past efforts to establish tree species on the linear corridors of the Little Smokey Drainage (Suncor Energy and ConocoPhillips 2005); site preparation and planting treatments were done between 3 and 7 years earlier. Cutlines and pipeline right-of-ways were treated by mounding, slash rollback, straight planting, seeding or had no treatments. We assessed tree size and growth of planted tree seedlings and the numbers of natural seedlings in 23 different locations across a variety of treatments and ecosites. Findings that there was usually poor growth of planted trees on upland seismic lines; mounding site preparation (without slash rollback) resulted in poor-moderate levels of growth of planted seedlings, while growth was uniformly poor on unprepared seismic cutlines. Lodgepole pine tended to have better growth than white spruce and black spruce. Pipeline right-of- ways where mineral and organic layers were admixed were the only linear corridors where good growth of planted trees was noted. The best natural regeneration of trees was observed on sites with slash rollback and coupled with mechanical treatment of the line. These sites also appeared to have the most variety of and growth of vascular plants. On lowland peatland sites, mounding treatments resulted in relatively good growth of planted black spruce. Mounds on lowland sites encouraged natural regeneration of black spruce.

Overall, the linear corridors reforested in the past program had lower levels of tree growth than would be expected if these trees were planted in forestry regeneration programs. In most of the upland sites, it will take decades before the planted seedlings will have a significant impact on the closure of these lines – in some cases treatments will be complete failures. Only treatments on some of the pipeline right-of-ways and peatland sites were producing good results. As linear corridors bisect many different soil and ecosystem types in a relatively short distance, planning for optimum treatments of a given length of corridor is exceptionally complex. Different species, stock types and planting positions on a general mechanical site preparation treatment such as mounding would be required. This complexity would take exceptionally high levels of understanding and planning by the workers trying to reforest these lines in order for success. Without exceptional effort and expertise, we recommend a simpler approach. It is likely that a combination of rollback of slash and topsoil and mechanical site preparation such as mounding would be a good general purpose treatment to achieve natural regeneration on most corridors. This type of treatment would produce opportunities for natural seeding of trees, while at the same time impede the use of these lines by both large mammals and recreation vehicles.