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On October 2nd between 15:47 and 16:27 I collected field data at Whispering Woods park, Calgary AB. The weather was a sunny 7°C with a light breeze. I took 10 replicates of P. tremuloides (aspen tree) from the bottom of the hill, and 10 from the top of the hill. I used a simple random sampling design to find these replicates. A random number generator was used to locate initial tree, then random number generator was used for subsequent replicates by counting the number of trees based on the random number. I walked from West to East and then back again when I reached the last tree on each side. This is a modification from my previous systematic sampling design. I believe is this new method is an improvement, as it allows me to take 10 replicates instead of 9 and uses a more random process.
This was the second day of snow melting since a large snowfall over the weekend, thus I anticipated having difficulties using my soil moisture probe. I predicted the forest floor to be too wet that the probe wouldn’t be able to record an accurate moisture level, or that the snow would skew all my data. However, it appeared that any leftover snow was sitting on the thick layer of native grasses, such that I only had to brush this snow away to isolate the untouched soil underneath. Thus, soil readings were no trouble. Other than this, I had no problems implementing my sampling design.
So far, the patterns observed have been mostly in favour of my predictions. At the bottom of the hill, the mean soil moisture has been higher at the base of the trees, the mean pH has been more neutral, and the mean percentage of yellow leaves, and leaves lost has been lower. Upon reflection, this appears to suggest that the soil conditions are more moist at the bottom of the hill, which serves as a proxy for tree health.
I look forward to collecting more data over the next few weeks to track these patterns further.
Madeleine Browne
