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To collect my field data, I established three transects through the 0.68 ha forest area under investigation and systematically placed six circle plots with a 5m radius 20 paces apart in each transect. Altogether there were 18 replicates. I am interested in the density of large Populus alba trees and the associated soil moisture, so at each circle plot I extracted a soil sample at the centre of the plot and measured the circumference of each large tree at breast height (above 25cm in circumference). I made sure to dig at least 10cm deep when collecting soil samples and removed any gross organic material before taking any measurements. My sampling design went quite smoothly; however, there was a recent snowstorm that covered my study area in snow, so walking and digging was more time consuming and I also had to be careful when extracting soil samples to not contaminate them with the surrounding snow. Once I got back to my house, I sorted through the soil samples to make sure there was no organic matter and then weighed them all, put them in the dehydrator at 115˚ F, then weighed them again. I used the resulting value to calculate the soil moisture content percentage.
While walking through the dense forest and seeing my data unfold before my eyes, I noticed that the centre transect was having a greater density of P. alba then my east transect. This was surprising to me because I initially believed that my peripheral transects were both denser in P. alba than the centre transect. When reflecting back to my current hypothesis (P. alba density is associated with soil moisture), this reaffirmed my suspicion that increasing soil moisture content was going to be associated with increasing P. alba density. This is because the tree density was increasing from east to west and there was a dyke near the west perimeter, so I assumed that soil moisture would similarly be increasing in a westward fashion.
