In 2022, GIS shapefiles were received from West Fraser Mills containing data from harvested cut blocks which were operationally treated with herbicide in 2021. 25 sites were selected for the establishment of sample plots (Figure 1). Sample sites were chosen based on access, spatial variability within Forest Management Agreement areas (FMA's) and across FMA's throughout the province to include sites from multiple natural subregions. Criteria for these selected sites were:

• Clearcuts that were replanted (either lodgepole pine or white spruce)

• Less than 10 years old

• Sprayed with herbicide by helicopter within the previous year (all sites were sprayed in 2021)

• Sprayed for stand-tending purposes 

All selected cut blocks were within one of West Fraser's FMA's including, Blue Ridge, Manning, Hinton, Edson, and Sundre. 

In 2023, GIS shapefiles were also received from West Fraser for cut blocks that had been replanted but not yet sprayed in Hinton and Blue Ridge. 13 untreated sites were selected to establish sampling plots in July 2023, and measurements were taken before they were sprayed. These same 13 sites were then treated with herbicide in August 2023 and will be re-measured in July 2024 to record post-treatment data (Figure 1).  

10 sampling plots were established in each of the selected cut blocks. The plots were constrained to mesic ecosites determined using the provincial Derived Ecosite Phase database (DEP). Sampling plots contained 3 nested plots as well as 2 quadrats, each measuring different criteria (Figure 2). 

• 5.64 m radius plot was used to record and measure any trees (DBH>5 cm, height>1.3 m)

• 3.57 m radius plot was used to record and measure willow and alder clumps (height>1.3 m, crown width north-south and east-west), as well as tally any living saplings (DBH<5 cm, height>1.3m)

• 1.78 m radius plot was used to tally any live seedlings (height 30 cm - 1.3 m)

• North and south quadrat (1 m2) was used to identify all plant species and record % cover

  • All plants of interest that were identified in the 1 m2 quadrat were then clipped outside of the plots across the cut block, and combined into one bag. This vegetation sample was then sent to the Agriculture and Food lab at the University of Guelph to be analyzed for glyphosate residue. 

These 10 plots were distributed across the cut block based on the area (Figure 3). For openings up to 5 ha, plots were 50 m apart. For openings between 5-10 ha, plots were 75 m apart. For openings greater than 10 ha, plots were placed 100 m apart. 

During the summer of 2023, destructive sampling for biomass was also done throughout each cut block for fireweed, raspberry, willow, and aspen plants. These species were chosen as indicators because they were widespread throughout each of the sites, and they are preferred moose browse species (Persson et al., 2007; Shafer, 1963). All vegetation was clipped up to a maximum twig diameter of 4 mm to capture the biomass of new shoots that a moose would typically browse (Danell et al, 1991; Persson et al, 2007; Shafer, 1963). Destructive samples were taken from outside of the established plots to prevent disturbing the plots. Biomass samples followed the same criteria as listed above - willow (Salix spp.) shrubs had a height >1.3 m, aspen (Populus tremuloides) saplings had a height >1.3 m, aspen (P. tremuloides) seedlings were between 30 cm - 1.3 m tall, and fireweed (Chamerion angustifolium) and raspberry (Rubus idaeus) were clipped in a 1 m2 quadrant after determining % cover. Each biomass sample was then weighed in the field using a scale and fresh weight was recorded with up to 2 decimal points of accuracy.