Blog Post 6: Data Collection

Hypothesis:  Soil moisture affects presence and quantity of bracket fungi on mixed species trees in the Oxbow Trail Park.

Due to flooding that submerged large sections of my original study site, I elected to find a new site to complete my project. The area I chose is the Oxbow Trail park on Vale Island in Hay River, Northwest Territories. This park is comprised of wild mixed wood forest and creeks that drain to the Great Slave Lake and adjacent Hay River. It is largely untouched and sees very little foot traffic. For this reason, it is a good place to spot wildlife, including lynx, black bears and beavers. The other great thing about my new site is that unlike the first location, it is teaming with fungi. While I had a challenging time locating enough replicates at my original study site along the Kiwanis Trail, I quickly realized this would not be a problem in the Oxbow park.

For my initial study site I planned to run multiple transects and find the nearest polypore-infected tree for each transect. This strategy was chosen since the polypore-infected trees were quite rare, occurring only every 50-100 trees.

Since the presence of polypore-infected trees is plentiful at the Oxbow site, I decided to revise my strategy to incorporate stratified random sampling using randomly placed plots. I chose the stratified random technique because there were three distinct areas that I wanted to include: 1) The creek bed, 2) the forested area north of the creek and 3) the swampy forest south of the creek. I found plot coordinates using a random number generator. I sampled a total of 24 replicates, 4 from the creek bed, 10 from the north forest and 10 from the swampy south forest. This stratified breakdown gave a more accurate representation of the overall spatial context and distribution of trees.  16 of the replicates had polypores on them and 8 did not. I chose to study soil moisture content for trees without polypores to have a more complete understanding of the soil moisture distribution throughout the area.

Initially I only planned to count the number of brackets on each replicate and then take a soil sample from the base of the tree. However, during my field collection activities I felt it was also important to record additional details such as whether the tree was deciduous or coniferous, if the tree was alive or not, and if it was clustered amongst other infected trees. These additional findings may add more context to the study, however for the time being I am focusing only on the variables of # of fungi brackets and soil moisture content. I quickly discovered that many trees had brackets that extended far higher than I was able to count. Therefore, I only counted brackets up to diameter at breast height (DBH = 1.3) and then noted if multiple brackets were observed above this.

I initially planned on obtaining soil samples that were 20cm deep, however I found getting to this depth to be challenging due to roots, organic litter and the size of my spade. I therefore adapted my strategy and obtained all samples at a depth of 15cm, and tried to obtain approximately 100g of soil from each replicate.

To obtain soil weight and moisture content, I dried all the samples at 400 Celsius for 2 hours. Prior to drying, I weighed all the samples in the baggies that I collected them in, accounting for the weight of the bag. Once weighed, I placed the samples in the oven in batches. A few samples needed slightly longer to dry as they were very saturated. I considered the soil samples sufficiently dry when they crumbled easily, and no moisture could be felt.  I reweighed the dry samples, accounting for the weight of the bowl, and then calculated the moisture weight and the soil moisture content percentage.

Now that my samples have been collected and calculations are complete, the next stage will be graphing the data and looking for any patterns or trends which will either support or reject my initial hypothesis.