ALPAC-01-013

Natural Reforestation on Seismic Lines and Wellsites in Comparison to Natural Burns or Logged Sites
Sponsor: 
Alberta Pacific Forest Industries Inc.
Lead Researcher: 
Terry Osko, OSKO Natural Resource Consulting, and Arin MacFarlane, University of Alberta, Edmonton
Body: 
The study evaluates natural regeneration of wellsites and seismic lines compared to natural regeneration of cutblocks and burns, the capability of wellsites and seismic lines to produce a forest, and the causes of permanent alteration of site capability.

The study took place on Alberta-Pacific’s Forest Management Agreement (FMA) area. Sites selected were deciduous dominated stands that had been established in the 1950s or earlier. The three age classes sampled ranged from 0-10 years, 11-20 years and greater than 20 years. The data for reforestation of cutblocks and burns was obtained from the previous study in the Alberta-Pacific FMA.

The study found that stem densities increased over time on wellsites, and that densities on seismic lines did not differ substantially among age classes. There was a rapid decline in stem density over time in both fire and cutblocks. Stem densities on seismic lines and wellsites were considerably lower than burns and cutblocks in the youngest and middle age classes, but were fairly similar in the oldest age class. Seismic lines and wellsites were more diverse in tree species composition than burns or cutblocks in every age class. Only 4% of stems on wellsites and 2% of stems on seismic lines were taller than 5 m after 28 years. In burns and cutblocks, 80% of the stems were taller than 5 m after 28 years. On sites older than 28 years the majority of stems on wellsites and seismic lines had diameters (at 1.4m) of 0-2 cm compared to burns and cutblocks which had diameters between 4 and 6 cm. Reforestation on seismic lines and wellsites differed considerably from cutblocks and burns, most likely due to differences in site conditions. Such differences may include changes in soil physical and chemical properties, soil nutrients, site hydrology, availability of propagales for regeneration, competition with sown agronomic forages and herbivory. Specific causes of poor forest productivity on wellsites and seismic lines need to be determined in order to assess the permanence of productivity loss, mitigate present losses in productivity and prevent future losses.