As we left the bog boardwalk to go the forest trail we noticed that we had to climb up to an area of deciduous trees (mostly alder). We descended again when we started on the forest trail. This was basically a dump site! In the 1970s the area was used as a dumping ground for debris excavated during the construction of Sedgewick Library at UBC (an underground building). It was Dr. Bert Brink (Professor of Agriculture, UBC) who was instrumental in putting a stop to it. There is still concern over the impact of the run-off from the debris to adjacent forest and bog ecosystems. Dr. Brink passed away in 2007 and is known not only for his conservation work, but also as a researcher and teacher.
There is an interesting contrast between the vegetation growing on the debris site and the surrounding hemlock forest and bog. It has become a grove of alder trees. Many folk think of alder trees as weeds. They are one of the first plants established after major disturbances like clear cutting, fire, etc. That is because they can grow in sites of poor nutrients by virtue of their symbiotic association with bacteria. Bacteria are the only organisms that can convert atmospheric nitrogen (called nitrogen fixation) into a form useable by other organisms such as plants. The roots of alder form nodules in which the bacteria (Frankia) live. The bacteria fix the nitrogen into ammonia which the plant can absorb and in turn the plant provides the bacteria with food (sugar and other nutrients).
Note: the Sedgewick Library has an above ground addition now and is called Koerner library.