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Data was collection was completed at Coquitlam River Trail, Friday, June 5th on a partly cloudy day. The temperature was 17 degrees Celcius. There is an abundance of growth in this area, which allowed me to be able to note which areas of the forest are shaded, and which are open to sunlight. The river is flowing steadily, and visible disturbance was present along the river’s edge, potentially due to overflow from snowmelt.
To get the most out of this project, I decided to double the length of my transects to 200 meters long. My original plan was to have 3 transects parallel to the river which were 100 meters long but found that there may not have been enough data if my transects were this short.
I sampled 3 replicates (3 transects parallel to the river) and used systematic sampling by area for my design. 10 quadrats were placed along each transect line, and data for Alnus rubra were collected, including the number present, and circumference of each. Soil moisture was tested in the center of each 10×10 meter quadrat with a soil moisture meter. Other trees within each quadrat were noted and circumference measured to assess for potential competitive interactions.
One issue I found with testing soil moisture, was that I was not always able to test the center of each plot due to gravel or rock. Therefore I tested the nearest patch of soil that was soft and able to read moisture. Now that the leaves are present on all plants, the identification of species has been much easier as opposed to winter.
My data collection supports my hypothesis that red alder require higher soil moisture. The quadrats with the highest soil moisture reading subsequently had more alder present. A pattern I noticed during sampling is that red alder and black cottonwood are both more abundant closer to the river. Red alder are the only trees that lean into the river, while the black cottonwood grow straight up. This leads me to believe that there may be competition between these two species since they were often found in the same quadrats. I would also like to learn more about the interactions between salmonberry and red alder, as they were found to be next to each other most of the time. Because of the difference in size of these two species, I don’t believe there is a competitive interaction here, but that they are able to co-exist. A factor may be that they both simply thrive in areas of higher soil moisture.
Julia Thompson
